Water soluble fibers with post process modifications and articles containing same

ABSTRACT

A fiber having a surface region and an interior region includes a polymer comprising at least one of a vinyl acetate moiety or a vinyl alcohol moiety, the fiber having a transverse cross-section including the interior region comprising the polymer having a first degree of hydrolysis and the surface region comprising the polymer having a second degree of hydrolysis greater than the first degree of hydrolysis.

PRIORITY CLAIM AND CROSS-REFERENCE

This application claims the benefit of U.S. Provisional Application No.63/033,601, filed Jun. 2, 2020, which application is expresslyincorporated by reference herein in its entirety.

FIELD

The present disclosure relates generally to water soluble fibers. Moreparticularly, the disclosure relates to water soluble fibers comprisingpolyvinyl alcohol modified after fiber formation by hydrolysis.

BACKGROUND

Nonwoven webs are traditionally used in many single-use consumerproducts including personal care products, such as bandages, diapercomponents, feminine care, and adult incontinence, and single-use wipes,such as in industrial applications, medical applications, cleaningapplications, and personal/baby care. Traditional chemistries used insuch products, e.g., viscose, polypropylene, or cotton fibers, aregenerally non-sustainable, non-biodegradable, are potential contributorsto microplastics, and are often disposed of incorrectly, such as byflushing down a toilet and entering wastewater treatment and sewagefacilities. Known wipes must be disposed of in a bin, which may not behygienic or convenient for a user. Improper disposal of these articlescan result in pipe clogs in the home, formation of “fatbergs” oraggregation of congealed mass of biodegradable and non-biodegradablematerials composed of congealed grease and cooking fat and disposablewipes in residential and municipal wastewater systems, contributing tooceanic microplastics, and require a change in consumer behavior.

The solubility profile and mechanism (e.g., hot-water soluble vs.cold-water soluble, readily soluble vs. delayed solubility or extendedrelease) of a water-soluble article may need to be adjusted based on theend use of the article. For articles including water-soluble fibers, thesolubility profile and mechanism are generally varied by selecting fiberforming materials having a degree of hydrolysis or degree ofpolymerization. However, the degree of hydrolysis and degree ofpolymerization of fiber forming materials also influence the ability ofthe fiber forming material to form fibers. Thus, a fiber formed of aparticular polymer having a desired degree of hydrolysis and degree ofpolymerization to provide a fiber having a desired solubility profilemay not be accessible as the fiber forming material may not survive thefiber making process.

SUMMARY

One aspect of the disclosure provides a method of treating a fiberincluding a hydrolyzable polymer such as a polymer comprising at leastone of a vinyl acetate moiety or a vinyl alcohol moiety having a degreeof hydrolysis of less than 100%, the method including admixing the fiberand a hydrolysis agent solution to increase the degree of hydrolysis ofat least a portion of the polymer in the fiber.

Another aspect of the disclosure provides a method of treating a fiberincluding a hydrolyzable polymer such as a polymer comprising at leastone of a vinyl acetate moiety or a vinyl alcohol moiety having a degreeof hydrolysis of less than 100%, the method including contacting asurface of the fiber with a hydrolysis agent solution to increase thedegree of hydrolysis of the polymer at in a region of the fibercomprising at least the surface of the fiber.

Another aspect of the disclosure provides a fiber prepared according tothe methods of the disclosure.

Another aspect of the disclosure provides a fiber having a surfaceregion and an interior region, the fiber comprising a hydrolyzablepolymer a polymer comprising at least one of a vinyl acetate moiety or avinyl alcohol moiety and the fiber having a transverse cross-sectioncharacterized by the polymer of the surface region having a greaterdegree of hydrolysis than the polymer of the interior region.Optionally, the transverse cross-section of the fiber is characterizedby an increasing gradient in the degree of hydrolysis of the polymerfrom the interior region to the surface region.

Another aspect of the disclosure provides a fiber comprising atransverse cross-section characterized by a core-sheath structure, alsoreferred to as a core-shell structure, the fiber having a first, coreregion, comprising a hydrolyzable polymer such as a polymer comprisingat least one of a vinyl acetate moiety or a vinyl alcohol moiety havinga degree of hydrolysis less than 100%, a second, shell region,comprising such a polymer having a degree of hydrolysis greater than thepolymer of the first region.

Another aspect of the disclosure provides a method of treating anonwoven web comprising a plurality of fibers comprising a hydrolyzablepolymer such as a polymer comprising at least one of a vinyl acetatemoiety or a vinyl alcohol moiety having a degree of hydrolysis of lessthan 100%, the method including contacting at least a portion of thenonwoven web with a hydrolysis agent solution to increase the degree ofhydrolysis of the polymer of the fibers of the portion of the nonwovenweb.

Another aspect of the disclosure provides a nonwoven web treatedaccording to the methods of the disclosure.

Another aspect of the disclosure provides a nonwoven web comprising afiber of the disclosure.

Another aspect of the disclosure provides a multilayer nonwoven webcomprising a first layer comprising a nonwoven web treated according tothe methods of the disclosure or a nonwoven web comprising a fiber ofthe disclosure.

Another aspect of the disclosure provides a pouch comprising a nonwovenweb according to the disclosure in the form of a pouch defining aninterior pouch volume.

Another aspect of the disclosure provides a sealed article comprising anonwoven web of the disclosure.

Another aspect of the disclosure provides a flushable article comprisinga nonwoven web of the disclosure.

Another aspect of the disclosure provides a wearable absorbent article,the article comprising an absorbent core having a wearer facing side andan outer facing side and a liquid acquisition layer, wherein the liquidacquisition layer comprises a nonwoven web of the disclosure.

Further aspects and advantages will be apparent to those of ordinaryskill in the art from a review of the following detailed description.While the fibers, nonwoven webs, pouches, articles and their methods ofmaking a susceptible of embodiments in various forms, the descriptionhereafter includes specific embodiments with the understanding that thedisclosure is illustrative and is not intended to limit the invention tothe specific embodiments described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

For further facilitating the understanding of the present disclosure,fourteen (14) drawing figures are appended hereto.

FIGS. 1A - 1D show a transverse cross-section of various fiber shapes,wherein the line indicates the diameter of the fiber.

FIG. 2A shows the transverse cross-section of a round fibercharacterized by a core-sheath structure, wherein the polymer of thesheath 202 has a higher degree of hydrolysis than the polymer of thecore 201.

FIG. 2B shows the transverse cross-section of a round fibercharacterized by an increasing gradient in the degree of hydrolysis ofthe polymer from an interior region 301 to a surface region 302.

FIG. 2C shows the transverse cross-section of a round fibercharacterized by the polymer having the same degree of hydrolysis acrossthe transverse cross-section.

FIG. 3 shows the transverse cross-section of a round fiber having afirst, core region 401, a second, sheath or shell region 402, and twointermediate regions 403A and 403B disposed between the first and secondregions, the cross section of the fiber characterized by an increasinggradient in the degree of hydrolysis of the polymer from the firstregion to the second region.

FIG. 4 is an illustration of a wire frame cage (shown with the top open,to better illustrate water-soluble pouches contained therein) for use inthe Liquid Release Test described herein.

FIG. 5 shows an apparatus for performing the Liquid Release Test,including a beaker resting on a stand, the stand holding a rod forlowering a cage into the beaker, the rod being fixable by a collar witha set screw (not shown).

FIG. 6A is a micrograph image of a nonwoven web of the disclosure havinga softness rating of 1.

FIG. 6B is a micrograph image of a nonwoven web of the disclosure havinga softness rating of 5.

FIG. 7 shows a nonwoven web noting the exterior surfaces of the web as100 and 101.

FIG. 8 illustrates an apparatus set-up used for measuring a shrinkagealong a longitudinal axis of a fiber with the fiber contacting water ata temperature in a range of from 10° C. to 23° C.

FIG. 9 shows ATR-FTIR results of fibers (Fiber A) before and after thefibers are treated with 0.05 M of a base (NaOH or KOH) in a solvent(methanol or 10% methanol/ 90% hexane) at 40° C. for 1 minute,respectively.

FIG. 10 shows fiber shrinkage along a longitudinal axis of differentfibers having different degrees of hydrolysis with the fiber contactingwater at a temperature of 10° C. or 23° C.

FIG. 11 shows rupture time (seconds) and disintegration time (seconds)of a nonwoven web having an exemplary fiber (Fiber A) before and afterexposed to heated methanol.

FIG. 12 shows rupture time (seconds) of nonwoven webs including fibershaving different degrees of hydrolysis.

FIG. 13 shows disintegration time (seconds) of nonwoven webs includingfibers having different degrees of hydrolysis.

FIG. 14 shows ATR-FTIR results of an interior (“inside”) region and asurface (“outside”) region of an exemplary block comprising a copolymerof vinyl acetate and vinyl alcohol.

DETAILED DESCRIPTION

As described in the Background, a fiber formed of a particular polymerhaving a desired degree of hydrolysis and degree of polymerization toprovide a fiber having a desired solubility profile may not beaccessible because the fiber forming material may not survive the fibermaking process. Accordingly, it would be advantageous to provide amethod for modifying the solubility profile of a fiber after fiberformation in order to access otherwise unavailable solubility profiles.

Additionally, as the solubility profile of a fiber or a water-solublearticle prepared therefrom can be designed for a particular end use, itwould be advantageous to provide a method for modifying the solubilityprofile of a fiber after fiber formation in order to manage inventory.The ability to post-process modify the degree of hydrolysis and, thus,the solubility profile of a fiber would advantageously allow access tovarious fiber types starting from one or a plurality of fiber types.

Provided herein are methods of treating fibers or a surface thereof toincrease the degree of hydrolysis of a hydrolyzable polymer that makesup the fiber or a surface thereof, by contacting the fiber or surfacethereof with a hydrolysis agent solution. The methods of the disclosurecan advantageously provide a fiber having an increase in the averagedegree of hydrolysis of a hydrolyzable polymer that makes up the fiber,a fiber having a core-sheath structure wherein the polymer of the sheathor surface region has a greater degree of hydrolysis than the polymer ofthe core or interior region, and/or a fiber having an increasinggradient of the degree of hydrolysis of the polymer that makes up thefiber, from an interior region to a surface region. Optionally, thehydrolyzable polymer comprises at least one of a vinyl acetate moiety ora vinyl alcohol moiety. As used herein, “at least one of a vinyl acetatemoiety or a vinyl alcohol moiety” and “a vinyl acetate moiety and/or avinyl alcohol moiety” describe an example hydrolyzable polymercomprising only a vinyl acetate moiety, only a vinyl alcohol moiety, orboth a vinyl acetate moiety and a vinyl alcohol moiety. In embodiments,the fibers of the disclosure are water-soluble prior to treatment withthe hydrolysis agent solution and remain water-soluble after treatmentwith the hydrolysis agent solution. In embodiments, the fibers of thedisclosure are cold-water soluble prior to treatment with the hydrolysisagent solution and are hot-water soluble after treatment with thehydrolysis agent solution. In embodiments, the fibers of the disclosureare cold-water soluble prior to treatment with the hydrolysis agentsolution and at least a portion of the exterior surface of the fiber ishot-water soluble after treatment with the hydrolysis agent solution. Inembodiments, the fiber is not water-soluble prior to treatment with thehydrolysis agent solution and the fiber is water-soluble after treatmentwith the hydrolysis agent solution. In embodiments, the fiber is notwater-soluble after admixing the fiber with the hydrolysis agent.

The methods and fibers of the disclosure can provide one or moreadvantages, including but not limited to, providing control over themicrostructure of the a fiber, modifying the solubility profile and/ormechanism of a fiber, enhancing the chemical compatibility of a fiber toa chemical agent, increasing the absorbance capacity of a fiber,increasing and/or controlling the loading of an active to the interiorof a fiber, and/or providing control over the release of a compositionor active from the interior of a fiber.

As used herein and unless specified otherwise, the term “water-soluble”refers to any nonwoven web or article containing same having adissolution time of 300 seconds or less at a specified temperature asdetermined according to MSTM-205 as set forth herein, or any fiberhaving complete dissolution time of less than 30 seconds at a specifiedtemperature according to the method for determining single fibersolubility disclosed herein. For example, the solubility parameters canbe characteristic of a nonwoven web having a thickness of 6 mil (about152 µm), or an article made therefrom. The dissolution time of thenonwoven web optionally can be 200 seconds or less, 100 seconds or less,60 seconds or less, or 30 seconds or less at a temperature of about 100°C., about 90° C., about 80° C., about 70° C., about 60° C., about 50°C., about 40° C., about 20° C., or about 10° C. In embodiments whereinthe dissolution temperature is not specified, the water-soluble nonwovenweb has a dissolution time of 300 seconds or less at a temperature nogreater than about 100° C. A fiber can have a complete dissolution timeof 30 seconds or less at a temperature of about 100° C., about 90° C.,about 80° C., about 70° C., about 60° C., about 50° C., about 40° C.,about 20° C., or about 10° C. As used herein, a fiber is “insoluble,”“water-insoluble,” or “insoluble in water” when the fiber has a completedissolution time of greater than 30 seconds at a specified temperatureaccording to the method for determining single fiber solubilitydisclosed herein. In embodiments wherein the complete dissolutiontemperature is not specified, a water-soluble fiber has a completedissolution time of 30 seconds or less at a temperature no greater thanabout 100° C. and a water-insoluble fiber has a complete dissolutiontime of greater than 30 seconds at a temperature no greater than about100° C. As used herein and unless specified otherwise, the term “coldwater-soluble” refers to any nonwoven web having a dissolution time of300 seconds or less at 10° C. as determined according to MSTM-205. Forexample, the dissolution time optionally can be 200 seconds or less, 100seconds or less, 60 seconds or less, or 30 seconds at 10° C. As usedherein and unless specified otherwise, the term “cold water-soluble” inconnection with a fiber refers to a fiber having a complete dissolutiontime of 30 seconds or less at a temperature of 10° C. or less, accordingto the Method for Determining Single Fiber Solubility disclosed herein.

As used herein and unless specified otherwise, the term“water-dispersible” refers to a nonwoven web, or article containing samewherein upon submersion in water at a specified temperature the nonwovenweb or article physically disassociates into smaller constituent pieces.The smaller pieces may or may not be visible to the naked eye, may ormay not remain suspended in the water, and may or may not ultimatelydissolve. In embodiments wherein a dispersion temperature is notspecified, the nonwoven web or pouch will disintegrate in 300 seconds orless at a temperature of about 100° C. or less, according to MSTM-205.For example, the disintegration time optionally can be 200 seconds orless, 100 seconds or less, 60 seconds or less, or 30 seconds or less ata temperature of about 80° C., about 70° C., about 60° C., about 50° C.,about 40° C., about 20° C., or about 10° C., according to MSTM-205. Forexample, such dispersion parameters can be characteristic of a nonwovenweb having a thickness of 6 mil (about 152 µm), or an article madetherefrom.

As used herein, the term “flushable” refers to an article such as anonwoven web, or pouch that is dispersible in aqueous environments, forexample, a liquid sewage system, such that the disposal of the web(s) orpouch(es) does not result in the catching of such articles within thepipes of a plumbing system or building up over time to cause a blockageof such a pipe. The INDA/EDANA standard for flushability requires thatgreater than 95% of the starting material must pass through a 12.5 mmsieve after 60 minutes of slosh box testing using 28 RPM and 18° tiltangle. The Flushability Test set forth herein provides a more stringentflushability test. A commercially available nonwoven web in the form ofa flushable wipe, herein referred to as Commercial Wipe A, is certifiedas flushable and has a disintegration time of 20 seconds as measured bythe Flushability Test set forth herein. Thus, as used herein and unlessspecified otherwise, the term “flushable” refers to an article such as anonwoven web or pouch that has a percent disintegration that meets orexceeds the percent degradation of Commercial Wipe A (20%) as measuredby the Flushability Test as set forth herein. Flushable nonwoven websand articles containing same have the advantage of being moreprocessable in recycling processes or can simply be flushed in, forexample, septic and municipal sewage treatment systems such that, afteruse, the web, structure, or pouch does not need to be landfilled,incinerated, or otherwise disposed of.

As used herein and unless specified otherwise, the term “nonwoven web”refers to a web or sheet comprising, consisting of, or consistingessentially of fibers arranged (e.g., by a carding process) and bondedto each other. Thus, the term nonwoven web can be considered short handfor nonwoven fiber-based webs. Further, as used herein, “nonwoven web”includes any structure including a nonwoven web or sheet, including, forexample, a nonwoven web or sheet having a film laminated to a surfacethereof. Methods of preparing nonwoven webs from fibers are well knownin the art, for example, as described in Nonwoven Fabrics Handbook,prepared by Ian Butler, edited by Subhash Batra et al., Printing byDesign, 1999, herein incorporated by reference in its entirety. As usedherein and unless specified otherwise, the term “film” refers to acontinuous film or sheet, e.g., prepared by a casting or extrusionprocess.

“Comprising” as used herein means that various components, ingredientsor steps that can be conjointly employed in practicing the presentdisclosure. Accordingly, the term “comprising” encompasses the morerestrictive terms “consisting essentially of” and “consisting of.” Thepresent compositions can comprise, consist essentially of, or consist ofany of the required and optional elements disclosed herein. For example,a thermoformed packet can “consist essentially of” a nonwoven webdescribed herein for use of its thermoforming characteristics, whileincluding a non-thermoformed film or nonwoven web (e.g., lid portion),and optional markings on the film, e.g., by inkjet printing. Thedisclosure illustratively disclosed herein suitably may be practiced inthe absence of any element or step which is not specifically disclosedherein.

All percentages, parts and ratios referred to herein are based upon thetotal dry weight of the nonwoven web or film composition or total weightof the packet content composition of the present disclosure, as the casemay be, and all measurements made are at about 25° C., unless otherwisespecified. All such weights as they pertain to listed ingredients arebased on the active level and therefore do not include carriers orby-products that may be included in commercially available materials,unless otherwise specified.

All ranges set forth herein include all possible subsets of ranges andany combinations of such subset ranges. By default, ranges are inclusiveof the stated endpoints, unless stated otherwise. Where a range ofvalues is provided, it is understood that each intervening value betweenthe upper and lower limit of that range and any other stated orintervening value in that stated range, is encompassed within thedisclosure. The upper and lower limits of these smaller ranges mayindependently be included in the smaller ranges, and are alsoencompassed within the disclosure, subject to any specifically excludedlimit in the stated range. Where the stated range includes one or bothof the limits, ranges excluding either or both of those included limitsare also contemplated to be part of the disclosure.

It is expressly contemplated that for any number value described herein,e.g., as a parameter of the subject matter described or part of a rangeassociated with the subject matter described, an alternative which formspart of the description is a functionally equivalent range surroundingthe specific numerical value (e.g., for a dimension disclosed as “40 mm”an alternative embodiment contemplated is “about 40 mm”).

As used herein, the terms packet(s) and pouch(es) should be consideredinterchangeable. In certain embodiments, the terms packet(s) andpouch(es), respectively, are used to refer to a container made using thenonwoven web and/or film, and to a fully-sealed container preferablyhaving a material sealed therein, e.g., in the form a measured dosedelivery system. The sealed pouches can be made from any suitablemethod, including such processes and features such as heat sealing,solvent welding, and adhesive sealing (e.g., with use of a water-solubleadhesive).

As used herein and unless specified otherwise, the terms “wt.%” and“wt%” are intended to refer to the composition of the identified elementin “dry” (non-water) parts by weight of the entire article orcomposition referred to, for example a nonwoven web or film, includingresidual moisture in the nonwoven web or film (when applicable), orlaminate structure, or parts by weight of a composition enclosed withina pouch (when applicable).

As used herein and unless specified otherwise, the term “PHR” (“phr”) isintended to refer to the composition of the identified element in partsper one hundred parts water-soluble polymer (whether PVOH or otherpolymers, unless specified otherwise) in the polymer-containing articlereferred to, e.g., a water-soluble film, a fiber, or a nonwoven web, ora solution used to make the fiber or film.

The nonwoven webs, pouches, and related articles and methods of makingand use are contemplated to include embodiments including anycombination of one or more of the additional optional elements,features, and steps further described below (including those shown inthe Examples and figures), unless stated otherwise.

Fiber Forming Materials

In general, the fibers of the disclosure can include a single fiberforming material or a combination (i.e., blend) of fiber formingmaterials. A single fiber can include one of more water-soluble fiberforming materials, one or more non-water-soluble fiber formingmaterials, or a combination of water-soluble and non-water-soluble fiberforming materials. The fibers of the disclosure can generally include asynthetic fiber forming material, a natural fiber forming material, aplant based fiber forming material, a bio-based fiber forming material,a biodegradable fiber forming material, a compostable fiber formingmaterial, or a combination thereof. Plant-based fiber forming materialscan be naturally occurring (e.g., cotton) or reconstituted (e.g.,bamboo).

In general, the fibers of the disclosure include a fiber formingmaterial that, prior to contact with a hydrolysis agent, includes ahydrolyzable group. Hydrolyzable groups generally include (a) anyfunctional group that can be substituted with a nucleophile, such aswater or a hydroxyl ion, in the presence of an acid or base catalyst,(b) cyclic functional groups that can be opened with a nucleophile(e.g., cyclic esters such as a lactone), (c) functional groups that canbe cleaved with water in the presence of an enzyme to provide an —OHmoiety on the polymer backbone, and/or (d) any functional group that canbe reduced to provide an —OH moiety on the polymer backbone. Suitablehydrolyzable groups include, but are not limited to, esters, amides,ethers, acetals, nitriles, sulfhydryls, or a combination thereof.Suitable polymers including a hydrolyzable group include polyvinylacetate, polyvinyl propionate, polyvinyl alcohol polymers having adegree of hydrolysis of less than 100%, poly(N-vinylacetamide) polymers,polyvinyl butyral polymers, poly(butyl acrylate) polymers, poly(butylmethacrylate) polymers, cellulose acetate polymers, polyacrylonitrilepolymers, poly(N-isopropylacrylamide) polymers,poly(N,N-diethylacrylamide) polymers, poly(N,N-dimethylacrylamide)polymers, polyl(methylvinylether) polymers, poly(N,N-dimethylaminoethylmethacrylate) polymers, poly(N-vinylformamide) polymers,poly(N-vinylcaprolactam) polymers, polyvinylpyrrolidone polymers,polylactic acid, and combinations thereof.

In embodiments, the fibers of the disclosure include a polymercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety. Such a polymer is hydrolyzable. Unless expressly indicatedotherwise, the term “a polymer comprising at least one of a vinylacetate moiety or a vinyl alcohol moiety” as used herein will beunderstood to encompass any polymer having at least one moiety resultingfrom only vinyl acetate, only vinyl alcohol, or both vinyl acetate andvinyl alcohol. In some embodiments, suitable examples of such a polymer(or the polymer) include, without limitation, a polyvinyl alcoholhomopolymer, a polyvinyl acetate homopolymer, a polyvinyl alcoholcopolymer, a modified polyvinyl alcohol copolymer, and combinationsthereof. For example, the polyvinyl alcohol copolymer is a copolymer ofvinyl acetate and vinyl alcohol in some embodiments. For example, insome embodiments, the modified polyvinyl alcohol copolymer comprises ananionically modified copolymer, which may be a copolymer of vinylacetate and vinyl alcohol further comprising additional groups such as acarboxylate, a sulfonate, or combinations thereof. Such a polymercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety may also include an additional polymer, for example, in a blend.

Unless expressly indicated otherwise, the term “degree of hydrolysis” isunderstood as a percentage (e.g., a molar percentage) of hydrolyzedmoieties among all hydrolyzable moieties a polymer initially has. Forexample, for a polymer comprising at least one of a vinyl acetate moietyor a vinyl alcohol moiety, partial replacement of an ester group invinyl acetate moieties with a hydroxyl group occurs during hydrolysis,and a vinyl acetate moiety becomes a vinyl alcohol moiety. The degree ofhydrolysis of a polyvinyl acetate homopolymer is considered as zero,while the degree of hydrolysis of a polyvinyl alcohol homopolymer is100%. The degree of hydrolysis of a copolymer of vinyl acetate and vinylalcohol is equal to a percentage of vinyl alcohol moieties among a totalof vinyl acetate and vinyl alcohol moieties, and is between zero and100%.

Polyvinyl alcohol is a synthetic polymer that can be prepared by thealcoholysis, also termed hydrolysis or saponification, of polyvinylacetate. Fully hydrolyzed PVOH, where virtually all the acetate groupshave been converted to alcohol groups, is a strongly hydrogen-bonded,highly crystalline polymer which dissolves only in hot water - greaterthan about 140° F. (about 60° C.). If a sufficient number of acetategroups are allowed to remain after the hydrolysis of polyvinyl acetate,that is the polymer is partially hydrolyzed, then the polymer is moreweakly hydrogen-bonded, less crystalline, and is generally soluble incold water - less than about 50° F. (about 10° C.). As such, thepartially hydrolyzed polymer is a vinyl alcohol-vinyl acetate copolymerthat is a PVOH copolymer, but is commonly referred to as “polyvinylalcohol (PVOH)” or “the PVOH polymer.” For brevity, the term “the PVOHpolymer” used herein is understood to encompass a homopolymer, acopolymer, and a modified copolymer comprising vinyl alcohol moieties,for example, 50% or higher of vinyl alcohol moieties.

The fibers described herein can include polyvinyl acetate, one or morepolyvinyl alcohol (PVOH) homopolymers, one or more polyvinyl alcoholcopolymers, or a combination thereof. As used herein, the term“homopolymer” generally includes polymers having a single type ofmonomeric repeating unit (e.g., a polymeric chain consisting of orconsisting essentially of a single monomeric repeating unit). For theparticular case of “PVOH,” the term “the PVOH polymer” as an example ofa hydrolyzable polymer or a polymer comprising at least one of a vinylacetate moiety or a vinyl alcohol moiety includes copolymers consistingof a distribution of vinyl alcohol monomer units and vinyl acetatemonomer units, depending on the degree of hydrolysis (e.g., a polymericchain consisting of or consisting essentially of vinyl alcohol and vinylacetate monomer units). In the limiting case of 100% hydrolysis, a PVOHhomopolymer can include a true homopolymer having only vinyl alcoholunits. In some embodiments, the fibers and/or films of the disclosureinclude such a polymer comprising at least one of a vinyl acetate moietyor a vinyl alcohol moiety. In some embodiments, the fibers and/or filmsof the disclosure include a hot water-soluble polymer comprising atleast one of a vinyl acetate moiety or a vinyl alcohol moiety.

In some embodiments, the hydrolyzable polymer described herein includesa modified polyvinyl alcohol, for example, a copolymer. The modifiedpolyvinyl alcohol can include a copolymer or higher polymer (e.g.,ter-polymer) including one or more monomers in addition to the vinylacetate/vinyl alcohol groups. Optionally, the modification is neutral,e.g., provided by an ethylene, propylene, N-vinylpyrrolidone or othernon-charged monomer species. Optionally, the modification is a cationicmodification, e.g., provided by a positively charged monomer species.Optionally, the modification is an anionic modification. Thus, in someembodiments, the polyvinyl alcohol includes an anionic modifiedpolyvinyl alcohol. An anionic modified polyvinyl alcohol can include apartially or fully hydrolyzed PVOH copolymer that includes an anionicmonomer unit, a vinyl alcohol monomer unit, and optionally a vinylacetate monomer unit (i.e., when not completely hydrolyzed). In someembodiments, the PVOH copolymer can include two or more types of anionicmonomer units. General classes of anionic monomer units which can beused for the PVOH copolymer include the vinyl polymerization unitscorresponding to sulfonic acid vinyl monomers and their esters,monocarboxylic acid vinyl monomers, their esters and anhydrides,dicarboxylic monomers having a polymerizable double bond, their estersand anhydrides, and alkali metal salts of any of the foregoing. Examplesof suitable anionic monomer units include the vinyl polymerization unitscorresponding to vinyl anionic monomers including vinyl acetic acid,maleic acid, monoalkyl maleate, dialkyl maleate, maleic anhydride,fumaric acid, monoalkyl fumarate, dialkyl fumarate, itaconic acid,monoalkyl itaconate, dialkyl itaconate, citraconic acid, monoalkylcitraconate, dialkyl citraconate, citraconic anhydride, mesaconic acid,monoalkyl mesaconate, dialkyl mesaconate, glutaconic acid, monoalkylglutaconate, dialkyl glutaconate, glutaconic anhydride, alkyl acrylates,alkyl alkacrylates, vinyl sulfonic acid, allyl sulfonic acid, ethylenesulfonic acid, 2-acrylamido-1-methyl propane sulfonic acid,2-acrylamide-2-methylpropanesulfonic acid,2-methylacrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl acrylate,alkali metal salts of the foregoing (e.g., sodium, potassium, or otheralkali metal salts), esters of the foregoing (e.g., methyl, ethyl, orother C₁-C₄ or C₆ alkyl esters), and combinations of the foregoing(e.g., multiple types of anionic monomers or equivalent forms of thesame anionic monomer). In some embodiments, the PVOH copolymer caninclude two or more types of monomer units selected from neutral,anionic, and cationic monomer units.

The level of incorporation of the one or more monomer units/level ofmodification in the PVOH copolymers is not particularly limited. Inembodiments, the one or more monomer units / modifications are presentin the PVOH copolymer in an amount in a range of about 1 mol.% or 2mol.% to about 6 mol.% or 10 mol.% (e.g., at least 1.0, 1.5, 2.0, 2.5,3.0, 3.5, or 4.0 mol.% and/or up to about 3.0, 4.0, 4.5, 5.0, 6.0, 8.0,or 10 mol.% in various embodiments). In embodiments, the modification isan anionic modification and the anionic monomer units are present in thePVOH copolymer in an amount in a range of about 1 mol.% or 2 mol.% toabout 6 mol.% or 10 mol.% (e.g., at least 1.0, 1.5, 2.0, 2.5, 3.0, 3.5,or 4.0 mol.% and/or up to about 3.0, 4.0, 4.5, 5.0, 6.0, 8.0, or 10mol.% in various embodiments).

Polyvinyl alcohols can be subject to changes in solubilitycharacteristics. The acetate group in the co-poly(vinyl acetate vinylalcohol) polymer (PVOH copolymer) is known by those skilled in the artto be hydrolysable by either acid or alkaline hydrolysis. As the degreeof hydrolysis increases, a polymer composition made from the PVOHcopolymer will have increased mechanical strength but reduced solubilityat lower temperatures (e.g., requiring hot water temperatures fordissolution). Accordingly, exposure of a PVOH copolymer to an alkalineenvironment (e.g., resulting from a laundry bleaching additive) cantransform the polymer from one which dissolves rapidly and entirely in agiven aqueous environment (e.g., a cold water medium) to one whichdissolves slowly and/or incompletely in the aqueous environment,potentially resulting in undissolved polymeric residue at the end of awash cycle.

PVOH copolymers with pendant carboxyl groups, such as, for example,vinyl alcohol/hydrolyzed methyl acrylate sodium salt polymers, can formlactone rings between neighboring pendant carboxyl and alcohol groups,thus reducing the water solubility of the PVOH copolymer. In thepresence of a strong base, the lactone rings can open over the course ofseveral weeks at relatively warm (ambient) and high humidity conditions(e.g., via lactone ring-opening reactions to form the correspondingpendant carboxyl and alcohol groups with increased water solubility).Thus, contrary to the effect observed with a PVOH copolymer withoutpendant carboxyl groups, it is believed that such a PVOH copolymer canbecome more soluble due to chemical interactions between the polymer andan alkaline composition inside a pouch during storage.

Specific sulfonic acids and derivatives thereof having polymerizablevinyl bonds can be copolymerized with vinyl acetate to providecold-water-soluble PVOH polymers which are stable in the presence ofstrong bases. The base-catalyzed alcoholysis products of thesecopolymers, which are used in the formulation of water-soluble film, arevinyl alcohol-sulfonate salt copolymers which are rapidly soluble. Thesulfonate group in the PVOH copolymer can revert to a sulfonic acidgroup in the presence of hydrogen ions, but the sulfonic acid groupstill provides excellent cold-water solubility of the polymer. Inembodiments, vinyl alcohol-sulfonate salt copolymers contain no residualacetate groups (i.e., are fully hydrolyzed) and therefore are notfurther hydrolysable by either acid or alkaline hydrolysis. Generally,as the amount of modification increases, the water solubility increases,thus sufficient modification via sulfonate or sulfonic acid groupsinhibit hydrogen bonding and crystallinity, enabling solubility in coldwater. In the presence of acidic or basic species, the copolymer isgenerally unaffected, with the exception of the sulfonate or sulfonicacid groups, which maintain excellent cold water solubility even in thepresence of acidic or basic species. Examples of suitable sulfonic acidcomonomers (and/or their alkali metal salt derivatives) include vinylsulfonic acid, allyl sulfonic acid, ethylene sulfonic acid,2-acrylamido-1-methylpropanesulfonic acid,2-acrylamido-2-methylpropanesufonic acid,2-methacrylamido-2-methylpropanesulfonic acid and 2-sulfoethyl acrylate,with the sodium salt of 2-acrylamido-2-methylpropanesulfonic acid (AMPS)being a preferred comonomer.

The fiber forming polymers, whether polyvinyl alcohol polymers orotherwise, can be blended. When the polymer blend includes a blend ofpolyvinyl alcohol polymers, the PVOH polymer blend can include a firstPVOH polymer (“first PVOH polymer”), which can include a PVOH copolymeror a modified PVOH copolymer including one or more types of anionicmonomer units (e.g., a PVOH ter- (or higher co-) polymer), and a secondPVOH polymer (“second PVOH polymer”), which can include a PVOHcomopolymer or a modified PVOH copolymer including one or more types ofanionic monomer units (e.g., a PVOH ter- (or higher co-) polymer). Insome aspects, the PVOH polymer blend includes only the first PVOHpolymer and the second PVOH polymer (e.g., a binary blend of the twopolymers). Alternatively, or additionally, the PVOH polymer blend or afiber or nonwoven web made therefrom can be characterized as being freeor substantially free from other polymers (e.g., other polymersgenerally, other PVOH-based polymers specifically, or both). As usedherein, “substantially free” means that the first and second PVOHpolymers make up at least 95 wt.%, at least 97 wt.%, or at least 99 wt.%of the total amount of water-soluble polymers in the water-soluble fiberor film. In other aspects, the fiber can include one or more additionalwater-soluble polymers. For example, the PVOH polymer blend can includea third PVOH polymer, a fourth PVOH polymer, a fifth PVOH polymer, etc.(e.g., one or more additional PVOH copolymers or modified PVOHcopolymers, with or without anionic monomer units). For example, thefiber can include at least a third (or fourth, fifth, etc.)water-soluble polymer which is other than a PVOH polymer (e.g., otherthan PVOH copolymers or modified PVOH copolymers, with or withoutanionic monomer units).

The degree of hydrolysis (DH) of the PVOH copolymers included in thefibers of the present disclosure can be in a range of about 75% to about99.9% (e.g., about 79% to about 99.9%, about 79% to about 92%, about 80%to about 90%, about 88% to 92%, about 86.5% to about 89%, or about 88%,90% or 92% such as for cold-water-soluble compositions; about 90% toabout 99%, about 92% to about 99%, about 95% to about 99%, about 98% toabout 99%, about 98% to about 99.9%, about 96%, about 98%, about 99%, orgreater than 99%). As the degree of hydrolysis is reduced, a fiber madefrom the polymer will have reduced mechanical strength but fastersolubility at temperatures below about 20° C. As the degree ofhydrolysis increases, a fiber or film made from the polymer will tend tobe mechanically stronger and the thermoformability will tend todecrease. The degree of hydrolysis can be chosen such that thewater-solubility of the polymer is temperature dependent, and thus thesolubility of a fiber made from the polymer is also influenced. In oneoption the fiber is cold water-soluble. For a co-poly(vinyl acetatevinyl alcohol) polymer that does not include any other monomers (e.g., ahomopolymer not copolymerized with an anionic monomer) a coldwater-soluble fiber, soluble in water at a temperature of less than 10°C., can include PVOH with a degree of hydrolysis in a range of about 75%to about 90%, or in a range of about 80% to about 90%, or in a range ofabout 85% to about 90%. In another option the fiber is hotwater-soluble. For a co-poly(vinyl acetate vinyl alcohol) polymer thatdoes not include any other monomers (e.g., a homopolymer notcopolymerized with an anionic monomer) a hot water-soluble fiber,soluble in water at a temperature of at least about 60° C., can includePVOH with a degree of hydrolysis of at least about 98%.

The degree of hydrolysis of the polymer blend can also be characterizedby the arithmetic weighted, average degree of hydrolysis

$\overline{\left( H^{o} \right)}.$

For example,

$\overline{H^{o}}$

for a PVOH polymer that includes two or more PVOH polymers is calculatedby the formula

$\overline{H^{0}} = {\sum\left( {Wi \cdot H_{i}} \right)}$

where W_(i) is the molar percentage of the respective PVOH polymer andH_(i) is the respective degrees of hydrolysis. When a polymer isreferred to as having a specific degree of hydrolysis, the polymer canbe a single polyvinyl alcohol polymer having the specified degree ofhydrolysis or a blend of polyvinyl alcohol polymers having an averagedegree of hydrolysis as specified.

The viscosity of a PVOH polymer (µ) is determined by measuring a freshlymade solution using a Brookfield LV type viscometer with UL adapter asdescribed in British Standard EN ISO 15023-2:2006 Annex E BrookfieldTest method. It is international practice to state the viscosity of 4%aqueous polyvinyl alcohol solutions at 20° C. All viscosities specifiedherein in Centipoise (cP) should be understood to refer to the viscosityof 4% aqueous polyvinyl alcohol solution at 20° C., unless specifiedotherwise. Similarly, when a polymer is described as having (or nothaving) a particular viscosity, unless specified otherwise, it isintended that the specified viscosity is the average viscosity for thepolymer, which inherently has a corresponding molecular weightdistribution, i.e. the weighted natural log average viscosity asdescribed below. It is well known in the art that the viscosity of PVOHpolymers is correlated with the weight average molecular weight (Mw) ofthe PVOH polymer, and often the viscosity is used as a proxy for the Mw.

In embodiments, the PVOH polymer can have a viscosity of about 1.0 toabout 50.0 cP, about 1.0 to about 40.0 cP, or about 1.0 to about 30.0cP, for example about 4 cP, 8 cP, 15 cP, 18 cP, 23 cP, or 26 cP. Inembodiments, the PVOH homopolymers and/or copolymers can have aviscosity of about 1.0 to about 40.0 cP, or about 5 cP to about 23 cP,for example, about 1 cP, 1.5 cP, 2 cP, 2.5 cP, 3 cP, 3.5 cP, 4 cP, 4.5cP, 5 cP, 5.5 cP, 6 cP, 6.5 cP, 7 cP, 7.5 cP, 8 cP, 8.5 cP, 9 cP, 9.5cP, 10 cP, 11 cP, 12 cP, 13 cP, 14 cP, 15 cP, 17.5 cP, 18 cP, 19 cP, 20cP, 21 cP, 22 cP, 23 cP, 24 cP, 25 cP, 26 cP, 27 cP, 28 cP, 29 cP, 30cP, 31 cP, 32 cP, 33 cP, 34 cP, 35 cP, or 40 cP. In embodiments, thePVOH homopolymers and/or copolymers can have a viscosity of about 21 cPto 26 cP. In embodiments, the PVOH homopolymers and/or copolymers canhave a viscosity of about 5 cP to about 14 cP. In embodiments, the PVOHhomopolymers and/or copolymers can have a viscosity of about 5 cP toabout 23 cP.

For reference, in a polymer blend, the first PVOH polymer is denoted ashaving a first 4% solution viscosity at 20° C. (µ₁), and the second PVOHpolymer is denoted as having a second 4% solution viscosity at 20° C.(µ₂). In various embodiments, the first viscosity µ₁ can be in a rangeof about 4 cP to about 70 cP (e.g., at least about 4, 8, 10, 12, or 16cP and/or up to about 12, 16, 20, 24, 28, 30, 32, 35, 37, 40, 45, 48,50, 56, 60, or 70 cP, such as about 4 cP to about 70 cP, about 4 cP toabout 60 cP, about 4 cP to about 46 cP, about 4 cP to about 24 cP, about10 cP to about 16 cP, or about 10 cP to about 20 cP, or about 20 cP toabout 30 cP). Alternatively or additionally, the second viscosity µ₂ canbe in a range of about 4 cP to about 70 cP (e.g., at least about 4, 8,10, 12, or 16 cP and/or up to about 12, 16, 20, 24, 28, 30, 32, 35, 37,40, 45, 48, 50, 56, 60, or 70 cP, such as about 12 cP to about 30 cP,about 10 cP to about 16 cP, or about 10 cP to about 20 cP, or about 20cP to about 30 cP). When the PVOH polymer blend includes three or morePVOH polymers selected from PVOH polymer and PVOH copolymers, theforegoing viscosity values can apply to each PVOH polymer or PVOHcopolymer individually. Thus, the weight-average molecular weight of thewater-soluble polymers, including the first PVOH copolymer and thesecond PVOH copolymer, can be in a range of about 30,000 to about175,000, or about 30,000 to about 100,000, or about 55,000 to about80,000, for example. When referring to average viscosity of the PVOHpolymer blend, the weighted natural log average viscosity (̅µ) is used.The (µ̅) for a PVOH polymer that includes two or more PVOH polymers iscalculated by the formula

$\overline{\mu}\mspace{6mu} = \mspace{6mu} e^{\sum{W_{i} \cdot \mspace{6mu} 1\text{n}\mspace{6mu}\mu_{i}}}$

where µ_(i) is the viscosity for the respective PVOH polymers.

In embodiments wherein the water-soluble fiber includes a blend of apolyvinyl alcohol homopolymer and a polyvinyl alcohol copolymer, therelative amounts of homopolymer and copolymer are not particularlylimited. The polyvinyl alcohol homopolymer can make up about 15 wt.% toabout 70 wt.% of total weight of the water-soluble polymer blend, forexample, at least about 15 wt.%, at least about 20 wt.%, at least about25 wt.%, at least about 30 wt.%, at least about 40 wt.%, at least about50 wt.%, or at least about 60 wt.% and up to about 70 wt.%, up to about60 wt.%, up to about 50 wt.%, up to about 40 wt.%, or up to about 30wt.%, based on the total weight of the water-soluble polymer blend, andcan be a single homopolymer or a blend of one or more homopolymers(e.g., having a difference in viscosity and/or degree of hydrolysis).The remainder of the water-soluble polymer blend can be thewater-soluble polyvinyl alcohol copolymer. Without intending to be boundby theory, it is believed that as the amount of homopolymer decreasesbelow about 15 wt.%, the ability of the blend of polyvinyl alcoholhomopolymer and copolymer to form a fiber decreases. The water-solublepolyvinyl alcohol copolymer can make up about 30 wt.% to about 85 wt.%of the total weight of the water-soluble polymer blend, for example, atleast about 30 wt.%, at least about 40 wt.%, at least about 50 wt.%, atleast about 60 wt.%, at least about 70 wt.%, at least about 75 wt.%, orat least about 80 wt.%, and up to about 85 wt.%, up to about 80 wt.%, upto about 70 wt.%, up to about 60 wt.%, up to about 50 wt.%, or up toabout 40 wt.%, based on the total weight of the water-soluble polymerblend, and can be a single copolymer or a blend of one or morecopolymers. The blend can consist of a polyvinyl alcohol homopolymer anda polyvinyl alcohol copolymer. The blend can consist of a polyvinylalcohol homopolymer and a plurality of polyvinyl alcohol copolymers. Theblend can consist of more than one polyvinyl alcohol homopolymer andmore than one polyvinyl alcohol copolymer.

In embodiments, the fibers comprise polyvinyl acetate, a polyvinylalcohol homopolymer, a polyvinyl alcohol copolymer, a modified polyvinylalcohol copolymer, or a combination thereof. In embodiments, the fiberscomprise a polyvinyl alcohol homopolymer, a polyvinyl alcohol copolymer,a modified polyvinyl alcohol copolymer, or a combination thereof. Inembodiments, the fibers comprise a polyvinyl alcohol copolymer. Inembodiments, the fibers comprise a modified polyvinyl alcohol copolymer.In embodiments, the fibers comprise a polyvinyl alcohol copolymer thatis an anionically modified copolymer. In embodiment, the fibers comprisean anionically modified copolymer and the anionic modification comprisesa carboxylate, a sulfonate, or a combination thereof. In embodiments,the polyvinyl alcohol polymer is water-soluble prior to admixing thefiber with the hydrolysis agent solution. In embodiments, the polymerhas a degree of hydrolysis greater than about 79% and less than about99.9% (e.g., from about 79% to about 96%), prior to admixing the fiberwith the hydrolysis agent solution.

The fibers of the disclosure can include water-soluble polymers otherthan polyvinyl acetate and PVOH including, but are not limited to,polyacrylate, water-soluble acrylate copolymer, polyvinyl pyrrolidone,polyethylenimine, pullulan, water-soluble natural polymer including, butnot limited to, guar gum, gum Acacia, xanthan gum, carrageenan, andwater-soluble starch, water-soluble polymer derivatives including, butnot limited to, modified starches, ethoxylated starch, andhydroxypropylated starch, copolymers of the foregoing and a combinationof any of the foregoing additional polymers or copolymers. Yet otherwater-soluble polymers can include polyalkylene oxides, polyacrylamides,polyacrylic acids and salts thereof, water-soluble celluloses, celluloseethers, cellulose esters, cellulose amides, additional polyvinylacetate, polycarboxylic acids and salts thereof, polyamino acids,polyamides, gelatins, methylcelluloses, carboxymethylcelluloses andsalts thereof, dextrins, ethylcelluloses, hydroxyethyl celluloses,hydroxypropyl methylcelluloses, maltodextrins, polymethacrylates, andcombinations of any of the foregoing. Such water-soluble polymers,whether PVOH or otherwise are commercially available from a variety ofsources.

In embodiments, the fiber includes the polyvinyl alcohol polymer and anadditional polymer comprising a polyvinyl alcohol, a polyvinyl acetate,a polyacrylate, a water-soluble acrylate copolymer, a polyvinylpyrrolidone, a polyethylenimine, a pullulan, a guar gum, a gum Acacia, axanthan gum, a carrageenan, a starch, a modified starch, a polyalkyleneoxide, a polyacrylamide, a polyacrylic acid, a cellulose, a celluloseether, a cellulose ester, a cellulose amide, a polycarboxylic acid, apolyamino acid, a polyamide, a gelatin, dextrin, copolymers of theforegoing, and a combination of any of the foregoing additional polymersor copolymers.

The fibers can additionally include a water-insoluble fiber formingmaterial. Suitable water-insoluble fiber forming materials include, butare not limited to, cotton, polyester, copolyester, polyethylene (e.g.,high density polyethylene and low density polyethylene), polypropylene,wood pulp, fluff pulp, abaca, viscose, insoluble cellulose, insolublestarch, hemp, jute, flax, ramie, sisal, bagasse, banana fiber, lacebark,silk, sinew, catgut, wool, sea silk, mohair, angora, cashmere, collagen,actin, nylon, Dacron, rayon, bamboo fiber, modal, diacetate fiber,triacetate fiber, polyester, copolyester, polylactide (PLA),polyethylene terephthalate (PET), polypropylene (PP), and combinationsthereof. In embodiments, the water-insoluble fiber does not includecotton or rayon. In embodiments, the water-insoluble fiber compriseswool, diacetate, triacetate, nylon, PLA, PET, PP, or a combinationthereof.

The fibers can further comprise non-fiber forming materials, referred toherein as auxiliary or secondary ingredients. Auxiliary agents caninclude active agents and processing agents such as, but not limited toactive agents, plasticizers, plasticizer compatibilizers, surfactants,lubricants, release agents, fillers, extenders, cross-linking agents,antiblocking agents, antioxidants, detackifying agents, antifoams,nanoparticles such as layered silicate-type nanoclays (e.g., sodiummontmorillonite), bleaching agents (e.g., sodium metabisulfite, sodiumbisulfite or others), aversive agents such as bitterants (e.g.,denatonium salts such as denatonium benzoate, denatonium saccharide, anddenatonium chloride; sucrose octaacetate; quinine; flavonoids such asquercetin and naringen; and quassinoids such as quassin and brucine) andpungents (e.g., capsaicin, piperine, allyl isothiocyanate, andresinferatoxin), and other functional ingredients, in amounts suitablefor their intended purposes. As used herein and unless specifiedotherwise, “auxiliary agents” include secondary additives, processingagents, and active agents. Specific such auxiliary agents and processingagents can be selected from those suitable for use in water-solublefibers, water-insoluble fibers, nonwoven webs, or those suitable for usein water-soluble films.

In embodiments, the fibers of the disclosure are free of auxiliaryagents. As used herein and unless specified otherwise, “free ofauxiliary agents” with respect to the fiber means that the fiberincludes less than about 0.01 wt.%, less than about 0.005 wt.%, or lessthan about 0.001 wt.% of auxiliary agents, based on the total weight ofthe fiber.

A plasticizer is a liquid, solid, or semi-solid that is added to amaterial (usually a resin or elastomer) making that material softer,more flexible (by decreasing the glass-transition temperature of thepolymer), and easier to process. A polymer can alternatively beinternally plasticized by chemically modifying the polymer or monomer.In addition, or in the alternative, a polymer can be externallyplasticized by the addition of a suitable plasticizing agent. Water isrecognized as a very efficient plasticizer for PVOH and other polymers;including but not limited to water-soluble polymers, however, thevolatility of water makes its utility limited since polymer films needto have at least some resistance (robustness) to a variety of ambientconditions including low and high relative humidity.

The plasticizer can include, but is not limited to, glycerin,diglycerin, sorbitol, ethylene glycol, diethylene glycol, triethyleneglycol, dipropylene glycol, tetraethylene glycol, propylene glycol,polyethylene glycols up to 400 MW, neopentyl glycol, trimethylolpropane,polyether polyols, sorbitol, 2-methyl-1,3-propanediol (MPDiol®),ethanolamines, and a mixture thereof. The total amount of the non-waterplasticizer provided in a fiber can be in a range of about 1 wt. % toabout 45 wt.%, or about 5 wt.% to about 45 wt.%, or about 10 wt.% toabout 40 wt.%, or about 20 wt.% to about 30 wt.%, about 1 wt.% to about4 wt.%, or about 1.5 wt.% to about 3.5 wt.%, or about 2.0 wt.% to about3.0 wt.%, for example about 1 wt.%, about 2.5 wt.%, about 5 wt.%, about10 wt.%, about 15 wt.%, about 20 wt.%, about 25 wt.%, about 30 wt.%,about 35 wt.%, or about 40 wt.%, based on total fiber weight.

Surfactants for use in fibers are well known in the art. Surfactants foruse in films are also well known in the art and can suitably be used inthe fibers and/or nonwoven webs of the disclosure. Optionally,surfactants are included to aid in the dispersion of the fibers duringcarding. Suitable surfactants for fibers of the present disclosureinclude, but are not limited to, dialkyl sulfosuccinates, lactylatedfatty acid esters of glycerol and propylene glycol, lactylic esters offatty acids, sodium alkyl sulfates, polysorbate 20, polysorbate 60,polysorbate 65, polysorbate 80, alkyl polyethylene glycol ethers,lecithin, acetylated fatty acid esters of glycerol and propylene glycol,sodium lauryl sulfate, acetylated esters of fatty acids, myristyldimethylamine oxide, trimethyl tallow alkyl ammonium chloride,quaternary ammonium compounds, alkali metal salts of higher fatty acidscontaining about 8 to 24 carbon atoms, alkyl sulfates, alkylpolyethoxylate sulfates, alkylbenzene sulfonates, monoethanolamine,lauryl alcohol ethoxylate, propylene glycol, diethylene glycol, saltsthereof and combinations of any of the forgoing.

Suitable surfactants can include the nonionic, cationic, anionic andzwitterionic classes. Suitable surfactants include, but are not limitedto, propylene glycols, diethylene glycols, monoethanolamine,polyoxyethylenated polyoxypropylene glycols, alcohol ethoxylates,alkylphenol ethoxylates, tertiary acetylenic glycols and alkanolamides(nonionics), polyoxyethylenated amines, quaternary ammonium salts andquaternized polyoxyethylenated amines (cationics), alkali metal salts ofhigher fatty acids containing about 8 to 24 carbon atoms, alkylsulfates, alkyl polyethoxylate sulfates and alkylbenzene sulfonates(anionics), and amine oxides, N-alkylbetaines and sulfobetaines(zwitterionics). Other suitable surfactants include dioctyl sodiumsulfosuccinate, lactylated fatty acid esters of glycerin and propyleneglycol, lactylic esters of fatty acids, sodium alkyl sulfates,polysorbate 20, polysorbate 60, polysorbate 65, polysorbate 80,lecithin, acetylated fatty acid esters of glycerin and propylene glycol,and acetylated esters of fatty acids, and combinations thereof. Invarious embodiments, the amount of surfactant in the fiber is in a rangeof about 0.01 wt.%, to about 2.5 wt.%, about 0.1 wt.% to about 2.5 wt.%,about 1.0 wt.% to about 2.0 wt.%, about 0.01 wt% to 0.25 wt%, or about0.10 wt% to 0.20 wt%.

In embodiments, the fibers and/or nonwoven webs of the disclosure caninclude an active agent. The active agent can be added to the fiberitself, or during carding of the nonwoven web, and/or can be added tothe nonwoven web prior to bonding. Active agents added to the fibersduring carding can be distributed throughout the nonwoven web. Activeagents added to the nonwoven web after carding but prior to bonding canbe selectively added to one or both faces of the nonwoven web.Additionally, active agents can be added to the surface of pouches orother articles prepared from the nonwoven webs. In embodiments, theactive agent is provided as part of the plurality of fibers, dispersedwithin the nonwoven web, provided on a face of the nonwoven web, or acombination thereof.

The active agent, when present in the fiber and/or nonwoven web in anamount of at least about 1 wt%, or in a range of about 1 wt% to about 99wt%, provides additional functionality to the nonwoven web. Inembodiments, the active agent can comprise one or more componentsincluding, but not limited to, enzymes, oils, flavors, colorants, odorabsorbers, fragrances, pesticides, fertilizers, activators, acidcatalysts, metal catalysts, ion scavengers, detergents, disinfectants,surfactants, bleaches, bleach components, fabric softeners orcombinations thereof. In embodiments, the active agent can comprise acolorant, a surfactant, or a combination thereof. The active agent cantake any desired form, including as a solid (e.g., powder, granulate,crystal, flake, or ribbon), a liquid, a mull, a paste, a gas, etc., andoptionally can be encapsulated.

In certain embodiments, the active agent may comprise an enzyme.Suitable enzymes include enzymes categorized in any one of the sixconventional Enzyme Commission (EC) categories, i.e., theoxidoreductases of EC 1 (which catalyze oxidation/reduction reactions),the transferases of EC 2 (which transfer a functional group, e.g., amethyl or phosphate group), the hydrolases of EC 3 (which catalyze thehydrolysis of various bonds), the lyases of EC 4 (which cleave variousbonds by means other than hydrolysis and oxidation), the isomerases ofEC 5 (which catalyze isomerization changes within a molecule) and theligases of EC 6 (which join two molecules with covalent bonds). Examplesof such enzymes include dehydrogenases and oxidases in EC 1,transaminases and kinases in EC 2, lipases, cellulases, amylases,mannanases, and peptidases (a.k.a. proteases or proteolytic enzymes) inEC 3, decarboxylases in EC 4, isomerases and mutases in EC 5 andsynthetases and synthases of EC 6. Suitable enzymes from each categoryare described in, for example, U.S. Pat. No. 9,394,092, the entiredisclosure of which is herein incorporated by reference.

Enzymes for use in laundry and dishwashing applications can include oneor more of protease, amylase, lipase, dehydrogenase, transaminase,kinase, cellulase, mannanase, peptidase, decarboxylase, isomerase,mutase, synthetase, synthase, and oxido-reductase enzymes, includingoxido-reductase enzymes that catalyze the formation of bleaching agents.

Oils other than fragrances can include flavorants and colorants.

In one class of embodiments the active agent includes a flavor orcombination of flavors. Suitable flavors include but are not limited to,spearmint oil, cinnamon oil, oil of wintergreen (methylsalicylate),peppermint oils, and synthetic and natural fruit flavors, includingcitrus oils.

In some embodiments, the active agent may be a colorant or combinationof colorants. Examples of suitable colorants include food colorings,caramel, paprika, cinnamon, and saffron. Other examples of suitablecolorants can be found in U.S. Pat. No. 5,002,789, hereby incorporatedby reference in its entirety.

Another class of embodiments include one or more odor absorbers asactive agents. Suitable odor absorbers for use as active agentsaccording to the disclosure include, but are not limited to, zeolites,and complex zinc salts of ricinoleic acid. The odor absorbing activeagent can also comprise fixatives that are well known in the art aslargely odor-neutral fragrances, including but not limited to extractsof labdanum, styrax, and derivatives of abietic acid.

Another class of embodiments include one or more fragrances as activeagents. As used herein, the term fragrance refers to any applicablematerial that is sufficiently volatile to produce a scent. Embodimentsincluding fragrances as active agents can include fragrances that arescents pleasurable to humans, or alternatively fragrances that arescents repellant to humans, animals, and/or insects. Suitable fragrancesinclude, but are not limited to, fruits including, but not limited to,lemon, apple, cherry, grape, pear, pineapple, orange, strawberry,raspberry, musk and flower scents including, but not limited to,lavender-like, rose-like, iris-like and carnation-like. Optionally thefragrance is one which is not also a flavoring. Other fragrances includeherbal scents including, but not limited to, rosemary, thyme, and sage;and woodland scents derived from pine, spruce and other forest smells.Fragrances may also be derived from various oils, including, but notlimited to, essential oils, or from plant materials including, but notlimited to, peppermint, spearmint and the like. Suitable fragrant oilscan be found in U.S. Pat. No. 6,458,754, hereby incorporated byreference in its entirety.

Fragrances can include perfumes. The perfume may comprise neat perfume,encapsulated perfume, or mixtures thereof. Preferably, the perfumeincludes neat perfume. A portion of the perfume may be encapsulated in acore-shell encapsulate. In another type of embodiment, the perfume willnot be encapsulated in a core-shell encapsulate.

As used herein, the term “perfume” encompasses the perfume raw materials(PRMs) and perfume accords. The term “perfume raw material” as usedherein refers to compounds having a molecular weight of at least about100 g/mol and which are useful in imparting an odor, fragrance, essenceor scent, either alone or with other perfume raw materials. As usedherein, the terms “perfume ingredient” and “perfume raw material” areinterchangeable. The term “accord” as used herein refers to a mixture oftwo or more PRMs.

Applicable insect repellant fragrances include one or more ofdichlorvos, pyrethrin, allethrin, naled and/or fenthion pesticidesdisclosed in U.S. Pat. No. 4,664,064, incorporated herein by referencein its entirety. Suitable insect repellants are citronellal(3,7-dimethyl-6-octanal), N,N-diethyl-3-methylbenzamide (DEET),vanillin, and the volatile oils extracted from turmeric (Curcuma longa),kaffir lime (Citrus hystrix), citronella grass (Cymbopogon winterianus)and hairy basil (Ocimum americanum). Moreover, applicable insectrepellants can be mixtures of insect repellants.

In one class of embodiments, the active agents according to thedisclosure can comprise one or more pesticides. Suitable pesticides mayinclude, but are not limited to, insecticides, herbicides, acaricides,fungicides, and larvacides.

Another class of embodiments include one or more fertilizers as activeagents. As used herein, the term fertilizer applies to any applicablematerial that releases one or more of nitrogen, phosphorus, potassium,calcium, magnesium, sulfur, boron, chlorine, copper, iron, manganese,molybdenum, or zinc. Suitable fertilizers include, but are not limitedto zeolites. For example, clinoptilolite is a zeolite that releasespotassium and can also release nitrogen when preloaded with ammonium.

One class of embodiments comprise acid catalysts as active agents. Asused herein, the term acid catalysts refers to any species that servesas a proton source, thereby facilitating a chemical reaction. In onetype of embodiment, the acid catalyst will be a non-oxidizing organicacid. A suitable organic acid is para-toluenesulfonic acid. In someembodiments, active agents that are acid catalysts will facilitatereactions including, but not limited to, acetalization, esterificationor transesterification. Additional acid catalyzed reactions are wellknown in the art.

In one class of embodiments, active agents will include metal catalysts.These catalysts mediate reactions including, but not limited to,oxidation or reduction, hydrogenation, carbonylation, C—H bondactivation, and bleaching. Suitable metals for use as metal catalystsinclude, but are not limited to the VIIIA and IB transition metals, forexample, iron, cobalt, nickel, copper, platinum, rhodium, ruthenium,silver, osmium, gold and iridium. The metal that mediates catalysis canbe of any suitable oxidation state.

In alternative embodiments, the active agent may optionally be an ionscavenger. Suitable ion scavengers include, but are not limited to,zeolites. Optionally, zeolites can be added to water-soluble packetscomprising laundry detergents or dish washing detergents enclosedwithin, as a water softener.

Inorganic and organic bleaches are suitable cleaning active agents foruse herein. Inorganic bleaches include perhydrate salts including, butnot limited to, perborate, percarbonate, perphosphate, persulfate andpersilicate salts. The inorganic perhydrate salts are normally thealkali metal salts. Alkali metal percarbonates, particularly sodiumpercarbonate are suitable perhydrates for use herein. Organic bleachescan include organic peroxyacids including diacyl and tetraacylperoxides,especially, but not limited to, diperoxydodecanedioc acid,diperoxytetradecanedioc acid, and diperoxyhexadecanedioc acid. Dibenzoylperoxide is a suitable organic peroxyacid according to the disclosure.Other organic bleaches include the peroxy acids, particular examplesbeing the alkylperoxy acids and the arylperoxy acids.

In one class of embodiments, active agents can comprise bleachsensitizers, including organic peracid precursors that enhance thebleaching action in the course of cleaning at temperatures of 60° C. andbelow. Bleach sensitizers suitable for use herein include compoundswhich, under perhydrolysis conditions, give aliphatic peroxoycarboxylicacids having from 1 to 10 carbon atoms, or from 2 to 4 carbon atoms,and/or optionally substituted perbenzoic acid. Suitable substances bearO-acyl and/or N-acyl groups of the number of carbon atoms specifiedand/or optionally substituted benzoyl groups. Suitable substancesinclude, but are not limited to, polyacylated alkylenediamines, inparticular tetraacetylethylenediamine (TAED), acylated triazinederivatives, in particular1,5-diacetyl-2,4-dioxohexahydro-1,3,5-triazine (DADHT), acylatedglycolurils, in particular tetraacetylglycoluril (TAGU), N-acylimides,in particular N-nonanoylsuccinimide (NOSI), acylated phenolsulfonates,in particular n-nonanoyl- or isononanoyloxybenzenesulfonate (n- oriso-NOBS), carboxylic anhydrides, in particular phthalic anhydride,acylated polyhydric alcohols, in particular triacetin, ethylene glycoldiacetate and 2,5-diacetoxy-2,5-dihydrofuran and also triethylacetylcitrate (TEAC).

In embodiments that comprise fabric softeners as active agents, variousthrough-the-wash fabric softeners, especially the impalpable smectiteclays of U.S. Pat. 4,062,647, incorporated herein by reference in itsentirety, as well as other softener clays known in the art, canoptionally be used to provide fabric softener benefits concurrently withfabric cleaning. Clay softeners can be used in combination with amineand cationic softeners as disclosed, for example, in U.S. Pats.4,375,416 and 4,291,071, incorporated herein by reference in theirentireties.

In embodiments, the active agent can include disinfectants.Disinfectants suitable for use herein can include, but are not limitedto, hydrogen peroxide, inorganic peroxides and precursors thereof,sodium metabisulfite, quaternary ammonium cation based compounds,chlorine, activated carbon, and hypochlorite.

In embodiments, the active agent can include surfactants. Suitablesurfactants for use herein can include, but are not limited to,propylene glycols, diethylene glycols, monoethanolamine,polyoxyethylenated polyoxypropylene glycols, alcohol ethoxylates,alkylphenol ethoxylates, tertiary acetylenic glycols and alkanolamides(nonionics), polyoxyethylenated amines, quaternary ammonium salts andquaternized polyoxyethylenated amines (cationics), alkali metal salts ofhigher fatty acids containing about 8 to 24 carbon atoms, alkylsulfates, alkyl polyethoxylate sulfates and alkylbenzene sulfonates(anionics), amine oxides, N-alkylbetaines and sulfobetaines(zwitterionics), dioctyl sodium sulfosuccinate, lactylated fatty acidesters of glycerin and propylene glycol, lactylic esters of fatty acids,sodium alkyl sulfates, polysorbate 20, polysorbate 60, polysorbate 65,polysorbate 80, lecithin, acetylated fatty acid esters of glycerin andpropylene glycol, and acetylated esters of fatty acids, and combinationsthereof.

Active agents may be solids or liquids. Active agents that are solidscan have an average particle size (e.g., Dv50) of at least about 0.01µm, or a size in a range of about 0.01 µm to about 2 mm, for example.Liquid active agents may be applied directly to the nonwoven web, mixedwith a carrier powder, or microencapsulated. In embodiments thatcomprise a carrier powder, the average particle size of the carrierpowder can be at least about 0.01 µm, or in a range of about 0.01 µm toabout 2 mm, for example.

In one class of embodiments the active agent is encapsulated, allowingfor the controlled release of the active agent. Suitable microcapsulescan include or be made from one or more of melamine formaldehyde,polyurethane, urea formaldehyde, chitosan, polymethyl methacrylate,polystyrene, polysulfone, poly tetrahydrofuran, gelatin, gum arabic,starch, polyvinyl pyrrolidone, carboxymethylcellulose,hydroxyethylcellulose, methylcellulose, arabinogalactan, polyvinylalcohol, polyacrylic acid, ethylcellulose, polyethylene,polymethacrylate, polyamide, poly (ethylenevinyl acetate), cellulosenitrate, silicones, poly(lactideco-glycolide), paraffin, carnauba,spermaceti, beeswax, stearic acid, stearyl alcohol, glyceryl stearates,shellac, cellulose acetate phthalate, zein, and combinations thereof. Inone type of embodiment, the microcapsule is characterized by a meanparticle size (e.g., Dv50) of at least about 0.1 micron, or in a rangeof about 0.1 micron to about 200 microns, for example. In alternateembodiments, the microcapsules can form agglomerates of individualparticles, for example wherein the individual particles have a meanparticle size of at least about 0.1 micron, or in a range of about 0.1micron to about 200 microns.

The fibers to be treated can be formed by any process known in the art,for example, wet cool gel spinning, thermoplastic fiber spinning, meltblowing, spun bonding, electro-spinning, rotary spinning, continuousfilament producing operations, tow fiber producing operations, andcombinations thereof.

In embodiments, the fibers comprise fibers formed by wet cool gelspinning, melt blowing, spun bonding, or a combination thereof. Inembodiments, the fibers comprise fibers that are formed by wet cool gelspinning. In embodiments, the fibers comprise water-soluble fibers andnonwoven webs prepared therefrom are formed in a continuous melt blownprocess. In embodiments, the fibers comprise water-soluble fibers andnonwoven webs prepared therefrom are formed in a continuous spun bondprocess. It is standard in the art to refer to fibers and nonwoven websby the process used to prepare the same. Thus, any reference herein to,for example, a “melt blown fiber” or a “carded nonwoven web” should notbe understood to be a product-by-process limitation for a particularmelt blown or carding method, but rather merely identifying a particularfiber or web. Processing terms may therefore be used to distinguishfibers and/or nonwovens, without limiting the recited fiber and/ornonwoven to preparation by any specific process.

The fibers to be treated can be formed as bicomponent fibers. As usedherein, and unless specified otherwise, “bicomponent fibers” do notrefer to a fiber including a blend of fiber forming materials but,rather, refer to fibers including two or more distinct regions of fiberforming materials, wherein the composition of the fiber formingmaterials differ by region. Examples of bicomponent fibers include, butare not limited to, core-sheath (or core-shell) bicomponent fibers,island in the sea bicomponent fibers, and side-by-side bicomponentfibers. Core-sheath bicomponent fibers generally include a core having afirst composition of fiber forming materials (e.g., a single fiberforming material or a first blend of fiber forming materials) and asheath having a second composition of fiber forming materials (e.g., asingle fiber forming material that is different from the core material,or a second blend of fiber forming materials that is different from thefirst blend of fiber forming materials of the core). Island in the seabicomponent fibers generally include a first, continuous, “sea” regionhaving a first composition of fiber forming materials and discreet“island” regions dispersed therein having a second composition of fiberforming materials that is different from the first composition.Side-by-side bicomponent fibers generally include a first region runningthe length of the fiber and including a first composition of fiberforming materials adjacent to at least a second region running thelength of the fiber and including second composition of fiber formingmaterials that is different from the first composition.

The shape of the fiber is not particularly limited and can havetransverse cross-sectional shapes including, but is not limited to,round, oval (also referred to as ribbon), triangular (also referred toas delta), trilobal, and/or other multi-lobal shapes (FIG. 1 ). It willbe understood that the shape of the fiber need not be perfectlygeometric, for example, a fiber having a round transversecross-sectional shape need not have a perfect circle as the transversecross-sectional area, and a fiber having a triangular transversecross-sectional shape generally has rounded corners.

It will be understood that the diameter of a fiber refers to thetransverse cross-section diameter of the fiber along the longesttransverse cross-sectional axis. When a fiber is described as having (ornot having) a particular diameter, unless specified otherwise, it isintended that the specified diameter is the average diameter for thespecific fiber type referenced, i.e., a plurality of fibers preparedfrom polyvinyl alcohol fiber forming material has an arithmetic averagefiber diameter over the plurality of fibers. For shapes not typicallyconsidered to have a “diameter”, e.g., a triangle or a multi-lobalshape, the diameter refers to the diameter of a circle circumscribingthe fiber shape (FIG. 1 ).

The fibers of the disclosure may have a diameter in a range of about 10micron to 300 micron, for example, at least 10 micron, at least 15micron, at least 20 micron, at least 25 micron, at least 50 micron, atleast 100 micron, or at least 125 micron and up to about 300 micron, upto about 275 micron, up to about 250 micron, up to about 225 micron, upto about 200 micron, up to about 100 micron, up to about 50 micron, upto about 45 micron, up to about 40 micron, or up to about 35 micron forexample in a range of about 10 micron to about 300 micron, about 50micron to about 300 micron, about 100 micron to about 300 micron, about10 micron to about 50 micron, about 10 micron to about 45 micron, orabout 10 micron to about 40 micron. In embodiments, the fibers can havea diameter greater than 100 micron to about 300 micron. In embodiments,the fibers comprise cellulose and have a diameter in a range of about 10micron to about 50 micron, about 10 micron to about 30 micron, about 10micron to about 25 micron, about 10 micron to about 20 micron, or about10 micron to about 15 micron. In embodiments, the fibers comprise awater-soluble fiber forming material and have a diameter of about 50micron to about 300 micron, about 100 micron to about 300 micron, about150 micron to about 300 micron, or about 200 micron to about 300 micron.In embodiments, the diameters of a plurality of the water-soluble fibersused to prepare a nonwoven web of the disclosure have diameters that aresubstantially uniform. As used herein, fiber diameters are“substantially uniform” if the variance in diameter between fibers isless than 10%, for example 8% or less, 5% or less, 2% or less, or 1% orless. Fibers having substantially uniform diameters can be prepared by awet cooled gel spinning process or a thermoplastic fiber spinningprocess. Further, when a blend of fiber types are used, the averagediameter of the fiber blend can be determined using a weighted averageof the individual fiber types.

The fibers of the disclosure can be of any length. In embodiments, thelength of the fibers can be in a range of about 20 mm to about 100 mm,about 20 to about 90, about 30 mm to about 80 mm, about 10 mm to about60 mm, or about 30 mm to about 60 mm, for example, at least about 30 mm,at least about 35 mm, at least about 40 mm, at least about 45 mm, or atleast about 50 mm, and up to about 100 mm, up to about 95 mm, up toabout 90 mm, up to about 80 mm, up to about 70 mm, or up to about 60 mm.In embodiments, the length of the fibers can be less than about 30 mm orin a range of about 0.25 mm to less than about 30 mm, for example, atleast about 0.25 mm, at least about 0.5 mm, at least about 0.75 mm, atleast about 1 mm, at least about 2.5 mm, at least about 5 mm, at leastabout 7.5 mm, or at least about 10 mm and up to about 29 mm, up to about28 mm, up to about 27 mm, up to about 26 mm, up to about 25 mm, up toabout 20 mm, or up to about 15 mm. The fibers can be prepared to anylength by cutting and/or crimping an extruded polymer mixture. Inembodiments, the fiber can be a continuous filament, for example,prepared by processes such as spun bonding, melt blowing,electro-spinning, and rotary spinning wherein a continuous filament isprepared and provided directly into a web form. Further, when a blend offiber types are used, the average length of the fibers can be determinedusing a weighted average of the individual fiber types.

The fibers of the disclosure can have any length to diameter (L/D)ratio. In embodiments, length to diameter ratio of the fibers can begreater than about 2, greater than about 3, greater than about 4,greater than about 6, greater than about 10, greater than about 50,greater than about 60, greater than about 100, greater than about 200,greater than about 300, greater than about 400, or greater than about1000. Advantageously, the tactility of a nonwoven web can be controlledusing the L/D ratio of the fibers and the respective amounts of fibershaving various L/D ratios in the nonwoven composition. In general, asthe L/D of the fiber decreases, the stiffness and resistance to bendingincreases, providing a rougher hand feel. The fibers of the disclosuregenerally impart a rough feel to a nonwoven web including same, when thefibers have a low L/D ratio in a range of about 0.5 to about 15, orabout 0.5 to about 25, or about 1 to about 5. Such low L/D fibers can beprovided in a nonwoven web in an amount in a range of about 0 to about50% by weight, based on the total weight of the fibers in the nonwovenweb, for example, in a range of about 0.5 wt.% to about 25 wt.%, orabout 1 wt.% to about 15 wt.%. If the amount of low L/D fibers in anonwoven web is not known, the amount can be estimated by visualinspection of a micrograph of a nonwoven web. As shown in FIG. 6 , thepopulation of fibers having a visibly larger diameter and shorter cutrate, based on the total fiber population can be observed. FIG. 6A is amicrograph of a nonwoven web having 0% of low L/D fibers and a softnessrating of 1, whereas FIG. 6B is a micrograph of a nonwoven web having25% of low L/D fibers and a softness rating of 5.

The fibers of the disclosure can have any tenacity. The tenacity of thefiber correlates to the coarseness of the fiber. In general, as thetenacity of the fiber decreases the coarseness of the fiber increases.Fibers of the disclosure can have a tenacity in a range of about 1 toabout 100 cN/dtex, or about 1 to about 75 cN/dtex, or about 1 to about50 cN/dtex, or about 1 to about 45 cN/dtex, or about 1 to about 40cN/dtex, or about 1 to about 35 cN/dtex, or about 1 to about 30 cN/dtex,or about 1 to about 25 cN/dtex, or about 1 to about 20 cN/dtex, or about1 to about 15 cN/dtex, or about 1 to about 10 cN/dtex, or about 1 toabout 5 cN/dtex, or about 3 to about 8 cN/dtex, or about 4 to about 8cN/dtex, or about 6 to about 8 cN/dtex, or about 4 to about 7 cN/dtex,or about 10 to about 20, or about 10 to about 18, or about 10 to about16, or about 1 cN/dtex, about 2 cN/dtex, about 3 cN/dtex, about 4cN/dtex, about 5 cN/dtex, about 6 cN/dtex, about 7 cN/dtex, about 8cN/dtex, about 9 cN/dtex, about 10 cN/dtex, about 11 cN/dtex, about 12cN/dtex, about 13 cN/dtex, about 14 cN/dtex, or about 15 cN/dtex. Inembodiments, the fibers can have a tenacity of about 3 cN/dtex to about10 cN/dtex. In embodiments, the fibers can have a tenacity of about 7cN/dtex to about 10 cN/dtex. In embodiments, the fibers can have atenacity of about 4 cN/dtex to about 8 cN/dtex. In embodiments, thefibers can have a tenacity of about 6 cN/dtex to about 8 cN/dtex.

The fibers of the disclosure can have any fineness. The fineness of thefiber correlates to how many fibers are present in a transversecross-section of a yarn of a given thickness. Fiber fineness is theratio of fiber mass to length. The main physical unit of fiber finenessis 1 tex, which is equal to 1000 m of fiber weighing 1 g. Typically, theunit dtex is used, representing 1 g/10,000 m of fiber. The fineness ofthe fiber can be selected to provide a nonwoven web having suitablestiffness/hand-feel of the nonwoven web, torsional rigidity, reflectionand interaction with light, absorption of dye and/or otheractives/additives, ease of fiber spinning in the manufacturing process,and uniformity of the finished article. In general, as the fineness ofthe fibers increases the nonwovens resulting therefrom demonstratehigher uniformity, improved tensile strengths, extensibility and luster.Additionally, without intending to be bound by theory it is believedthat finer fibers will lead to slower dissolution times as compared tolarger fibers based on density. Further, without intending to be boundby theory, when a blend of fibers is used, the average fineness of thefibers can be determined using a weighted average of the individualfiber components. Fibers can be characterized as very fine (dtex ≤1.22), fine (1.22≤ dtex ≤ 1.54), medium (1.54≤ dtex ≤ 1.93), slightlycoarse (1.93≤ dtex ≤ 2.32), and coarse (dtex ≥2.32). The nonwoven web ofthe disclosure can include fibers that are very fine, fine, medium,slightly coarse, or a combination thereof. In embodiments, the fibershave a fineness in a range of about 1 dtex to about 10 dtex, about 1dtex to about 7 dtex, about 1 dtex to about 5 dtex, about 1 dtex toabout 3 dtex, or about 1.7 dtex to about 2.2 dtex. In embodiments,fibers have a fineness of about 1.7 dtex. In embodiments, fibers have afineness of about 2.2 dtex.

Wet Cooled Gel Spinning

In embodiments, the fibers of the disclosure are formed according to awet cooled gel spinning process, the wet cooled gel spinning processincluding the steps of

-   (a) dissolving the fiber forming material (polymers) in solution to    form a polymer mixture, the polymer mixture optionally including    auxiliary agents;-   (b) extruding the polymer mixture through a spinneret nozzle to a    solidification bath to form an extruded polymer mixture;-   (c) passing the extruded polymer mixture through a solvent exchange    bath;-   (d) optionally wet drawing the extruded polymer mixture; and-   (e) finishing the extruded polymer mixture to provide the fibers.

The solvent in which the fiber forming polymer is dissolved can suitablybe any solvent in which the polymer is soluble. In embodiments, thesolvent in which the polymer is dissolved includes a polar aproticsolvent. In embodiments, the solvent in which the polymer is dissolvedincludes dimethyl sulfoxide (DMSO).

In general, the solidification bath includes a cooled solvent forgelling the extruded polymer mixture. The solidification bath cangenerally be at any temperature that facilitates solidification of theextruded polymer mixture. The solidification bath can include a mixtureof a solvent in which the polymer is soluble and a solvent in which thepolymer is not soluble. The solvent, in which the polymer is notsoluble, is generally the primary solvent, wherein the solvent, in whichthe polymer is not soluble, makes up greater than 50% of the mixture.

After passing through the solidification bath, the extruded polymermixture gel can be passed through one or more solvent replacement baths.The solvent replacement baths are provided to replace the solvent inwhich the polymer is soluble with the solvent in which the polymer isnot soluble to further solidify the extruded polymer mixture and replacethe solvent in which the polymer is soluble with a solvent that willmore readily evaporate, thereby reducing the drying time. Solventreplacement baths can include a series of solvent replacement bathshaving a gradient of solvent in which the polymer is soluble with thesolvent in which the polymer is not soluble, a series of solventreplacement baths having only the solvent in which the polymer is notsoluble, or a single solvent replacement bath having only the solvent inwhich the polymer is not soluble.

Finished fibers are sometimes referred to as staple fibers, shortcutfibers, or pulp. In embodiments, finishing includes drying the extrudedpolymer mixture. In embodiments, finishing includes cutting or crimpingthe extruded polymer mixture to form individual fibers. Wet drawing ofthe extruded polymer mixture provides a substantially uniform diameterto the extruded polymer mixture and, thus, the fibers cut therefrom.Drawing is distinct from extruding, as is well known in the art. Inparticular, extruding refers to the act of making fibers by forcing theresin mixture through the spinneret head whereas drawing refers tomechanically pulling the fibers in the machine direction to promotepolymer chain orientation and crystallinity for increased fiber strengthand tenacity.

In embodiments wherein the fibers are prepared from a wet cooled gelspinning process, the fiber forming polymer can be generally any fiberforming polymer or blend thereof, e.g., two or more different polymers,as generally described herein. In refinements of the foregoingembodiments, the polymer(s) can have any degree of polymerization (DP),for example, in a range of 10 to 10,000,000, for example, at least 10,at least 20, at least 50, at least 100, at least 200, at least 300, atleast 400, at least 500, at least 750, or at least 1000 and up to10,000,000, up to 5,000,000, up to 2,500,00, up to 1,000,000, up to900,000, up to 750,000, up to 500,000, up to 250,000, up to 100,000, upto 90,000, up to 75,000, up to 50,000, up to 25,000, up to 12,000, up to10,000, up to 5,000, or up to 2,500, for example in a range of 1000 toabout 50,000, 1000 to about 25,000, 1000 to about 12,000, 1000 to about5,000, 1000 to about 2,500, about 50 to about 12,000, about 50 to about10,000, about 50 to about 5,000, about 50 to about 2,500, about 50 toabout 1000, about 50 to about 900, about 100 to about 800, about 150 toabout 700, about 200 to about 600, or about 250 to about 500. Inembodiments, the DP is at least 1,000. In embodiments, the fiber formingpolymer comprises a polyvinyl alcohol polymer having a degree ofpolymerization (DP) in a range of 1000 to about 50,000, 1000 to about25,000, 1000 to about 12,000, 1000 to about 5,000, 1000 to about 2,500,about 50 to about 12,000, about 50 to about 10,000, about 50 to about5,000, about 50 to about 2,500, about 50 to about 1000, about 50 toabout 900, about 100 to about 800, about 150 to about 700, about 200 toabout 600, or about 250 to about 500. In embodiments, the fiber formingpolymer comprises a polyvinyl alcohol polymer having a DP in a range of1000 to about 50,000, 1000 to about 25,000, 1000 to about 12,000, 1000to about 5,000, or 1000 to about 2,500.

The wet cooled gel spinning process advantageously provides one or morebenefits such as providing a fiber that includes a blend ofwater-soluble polymers, providing control over the diameter of thefibers, providing relatively large diameter fibers, providing controlover the length of the fibers, providing control over the tenacity ofthe fibers, providing high tenacity fibers, providing fibers frompolymers having a large degree of polymerization, and/or providingfibers which can be used to provide a self-supporting nonwoven web.Continuous processes such as spun bond, melt blown, electro-spinning androtary spinning generally do not allow for blending of water-solublepolymers (e.g., due to difficulties matching the melt index of variouspolymers), forming large diameter (e.g., greater than 50 micron) fibers,controlling the length of the fibers, providing high tenacity fibers, orthe use of polymers having a high degree of polymerization. Further, thewet cooled gel spinning process advantageously is not limited topolymers that are only melt processable and, therefore, can accessfibers made from fiber forming materials having very high molecularweights, high melting points, low melt flow index, or a combinationthereof, providing fibers having stronger physical properties anddifferent chemical functionalities compared to fibers prepared by a heatextrusion process.

Methods of preparing staple fibers and continuous fibers are well knownin the art. Once the staple fibers or continuous fibers are carded, thenonwoven web is bonded. Methods of bonding staple fibers are well knownin the art and can include through air bonding (thermal), calendarbonding (thermal with pressure), and chemical bonding. The nonwoven webof the disclosure can be thermally or chemically bonded. The nonwovenweb can be generally porous with varying pore size, morphology and webheterogeneity. Fiber physical properties and the type of bonding canaffect the porosity of the resulting nonwoven web. Calendar bonding isachieved by applying heat and pressure, and typically maintains the poresize, shape, and alignment produced by the carding process. Theconditions for calendar bonding can be readily determined by one ofordinary skill in the art. In general, if the heat and/or pressureapplied is too low, the fibers will not sufficiently bind to form afree-standing web and if the heat and/or pressure is too high, thefibers will begin to meld together. The fiber chemistry dictates theupper and lower limits of heat and/or pressure for calendar bonding.Without intending to be bound by theory, it is believed that attemperatures above 235° C., polyvinyl alcohol based fibers degrade.Methods of embossment for calendar bonding of fibers are known. Theembossing can be a one-sided embossing or a double-sided embossing.Typically, embossing of water-soluble fibers includes one-sidedembossing using a single embossing roll consisting of an orderedcircular array and a steel roll with a plain surface. As embossing isincreased (e.g., as surface features are imparted to the web), thesurface area of the web is increased. Without intending to be bound bytheory, it is expected that as the surface are of the web is increased,the solubility of the web is increased. Accordingly, the solubilityproperties of the nonwoven web can be advantageously tuned by changingthe surface area through embossing.

In contrast to calendar bonding, chemical bonding uses a binder solutionof the waste polymer left over from preparing the fibers to coat thecarded fibers under pressure, which can result in smaller, less orderedpores relative to the pores as carded. The solvent can be any solventthat solubilizes the binder. The solvent of the chemical bondingsolution is water in some embodiments. Without intending to be bound bytheory, it is believed that if the polymer solution used for chemicalbonding is sufficiently concentrated and/or sufficient pressure isapplied, a nonporous water-dispersible nonwoven web can be formed. Thesolvent used in chemical bonding induces partial solubilization of theexisting fibers in the web to weld and bond the fibers together. Thepolyvinyl alcohol binder provided in the solution assists in the weldingprocess to provide a more mechanically robust web. The temperature ofthe polymer solution is not particularly limited and can be provided atroom temperature (about 23° C.).

In some embodiments, a second layer of fibers can be used to bond thenonwoven web. Without intending to be bound by theory, it is believedthat fibers prepared from by a melt blown process, for example,water-soluble fibers, can be used to bond the nonwoven web using anin-line process. In particular, a nonwoven web can be passed under amelt blown process station such that the melt blown fibers are depositedafter melt extrusion and as the melt blown fibers cool and solidify,they bond to each other and to the nonwoven web on which they aredeposited. Melt blown fibers can be micro- to nano- scale in length andcan be provided on the nonwoven web such that the melt blown fibers makeup about 15%, about 12%, about 10%, about 8%, about 6%, or about 5%, byweight of the final nonwoven web, based on the total weight of thefibers in the final nonwoven web. Without intending to be bound bytheory, it is believed that the inclusion of about 5% to about 15% ofmelt blown fibers can increase the mechanical integrity of the nonwovenweb, without substantially changing the solubility properties of thenonwoven web. In general, when a polyvinyl alcohol fiber formingmaterial is used to prepare a melt blown fiber, the polyvinyl alcoholpolymer will be a homopolymer or copolymer as melt blown processesrequire low viscosity and high melt flow index polymers.

Pore sizes can be determined using high magnification and orderedsurface analysis techniques including, but not limited toBrunauer-Emmett-Teller theory (BET), small angle X-ray scattering(SAXS), and molecular adsorption.

In general, the fibers of the disclosure can be formed by any fiberprocess known in the art and are then post-process treated byhydrolysis.

The disclosure provides a method of treating a fiber including ahydrolyzable polymer such as a polymer comprising at least one of avinyl acetate moiety or a vinyl alcohol moiety as described herein. Inembodiments, the method includes admixing a fiber comprising such apolymer having a degree of hydrolysis less than 100% and a hydrolysisagent solution to increase the degree of hydrolysis of at least aportion of the fiber. The hydrolysis agent solution can include ahydrolysis agent and a solvent. The degree of hydrolysis of the fiberafter admixing with the hydrolysis agent solution can be determinedaccording to the Titration Method or Attenuated TotalReflection-Fourier-Transform Infrared (ATR-FTIR) Spectroscopy disclosedherein. The Titration Method determines an average degree of hydrolysisfor a fiber. For a fiber characterized by a constant degree ofhydrolysis across a transverse cross-section of the fiber, the constantdegree of hydrolysis is the average degree of hydrolysis for the fiber.For a fiber characterized by a transverse cross-section of the fiberhaving a core-sheath type distribution or a gradient distribution of thedegree of hydrolysis, the Titration test provides the average degree ofhydrolysis across all sections of the fiber. As used herein, and unlessspecified otherwise, at least a portion of a fiber has an increaseddegree of hydrolysis if any portion of the fiber (e.g., exterior, sheathportion, interior) has an increased degree of hydrolysis after admixing,relative to the degree of hydrolysis of the starting fiber. It will beunderstood that an increase in degree of hydrolysis to any portion ofthe fiber will result in an increase in the average degree of hydrolysisof the fiber as determined by the Titration Method. Thus, it will beunderstood that the degree of hydrolysis of at least a portion of thepolymer in the fiber will have increased if the average degree ofhydrolysis of the fiber, as determined by the Titration Method, isgreater after admixing the fiber with the hydrolysis agent solution,relative to the average degree of hydrolysis of the fiber prior toadmixing. The technique of ATR-FTIR provides accurate measurements in adegree of hydrolysis on a surface of a sample based on the signalscorresponding to chemical groups, such as a carbonyl group.

In general, admixing can include immersing the fibers in the hydrolysisagent solution. In embodiments, admixing can include stirring themixture of the fibers and the hydrolysis agent solution.

In embodiments, the method comprises admixing the hydrolysis agentsolution and the fiber under conditions sufficient to provide apredetermined degree of hydrolysis and/or a predetermined degree ofhydrolysis increase to the fiber. In general, the degree of hydrolysisof the treated fiber and/or the increase in the degree of hydrolysis ofthe treated fiber can be designed and controlled by varying the reactionconditions. Reaction conditions that can be modified to provide apredetermined degree of hydrolysis and/or increase in degree ofhydrolysis include the selection of the hydrolysis agent, selection ofthe concentration of the hydrolysis agent in the hydrolysis agentsolution, reaction (admixing) time, reaction (admixing) temperature,selection of solvent for the hydrolysis agent solution, and optionalinclusion of an activator.

In general, as the reaction time increases, the degree of hydrolysiswill increase. Thus, the reaction time can be selected to provide adesired increase in the degree of hydrolysis of the polymer that makesup the fiber, e.g., a copolymer (or modified copolymer) having vinylacetate and vinyl alcohol moieties. The reaction time can be from about1 minute to about 48 hours, for example, about 1 minute to about 10minutes (e.g., 1 minute, 2 minutes, 5 minutes, or 10 minutes), about 2minutes to about 36 hours, about 2 minutes to about 24 hours, about 2minutes to about 12 hours, about 2 minutes to about 6 hours, about 2minutes to about 4 hours, about 2 minutes to about 2 hours, about 2minutes to about 1 hour, about 5 minutes to about 1 hour, about 5minutes to about 2 hours, about 5 minutes to about 5 hours, about 5minutes to about 10 hours, about 5 minutes to about 12 hours, about 5minutes to about 24 hours, about 10 minutes to about 24 hours, about 15minutes to about 24 hours, about 30 minutes to about 24 hours, about 1hour to about 24 hours, about 2 hours to about 24 hours, about 3 hoursto about 24 hours, about 4 hours to about 24 hours, about 5 hours toabout 24 hours, about 6 hours to about 24 hours, about 8 hours to about24 hours, about 10 hours to about 24 hours, about 12 hours to about 24hours, about 12 hours to about 18 hours, about 14 hours to about 20hours, or about 16 hours to about 24 hours. In embodiments, the admixingcan be for about 2 minutes to about 48 hours. In embodiments, theadmixing can be for about 12 to about 36 hours. In embodiments, theadmixing can be for about 18 to about 28 hours.

In general, as the temperature of the reaction is increased, the rate ofhydrolysis will increase. Thus, the temperature of the reaction can beselected in combination with reaction time to provide a desired increasein the degree of hydrolysis of the polymer that makes up the fiber,e.g., a copolymer (or modified copolymer) having vinyl acetate and vinylalcohol moieties. The temperature of the reaction is not particularlylimited so long as the fiber does not dissolve or decompose and thesolvent remains a liquid under the heating conditions. The reactiontemperature can be from about 10° C. to about 200° C., about 10° C. toabout 190° C., about 10° C. to about 180° C., about 10° C. to about 170°C., about 10° C. to about 160° C., about 10° C. to about 150° C., about10° C. to about 140° C., about 10° C. to about 130° C., about 10° C. toabout 120° C., about 10° C. to about 110° C., about 10° C. to about 100°C., about 10° C. to about 90° C., about 10° C. to about 80° C., about10° C. to about 70° C., about 10° C. to about 60° C., about 10° C. toabout 50° C., about 10° C. to about 40° C., about 10° C. to about 30°C., about 20° C. to about 100° C., about 20° C. to about 90° C., about20° C. to about 80° C., about 30° C. to about 100° C., about 30° C. toabout 90° C., about 30° C. to about 80° C., about 30° C. to about 70°C., about 30° C. to about 60° C., or about 30° C. to about 50° C.Without intending to be bound by theory, it is believed that at highertemperatures as the polarity of the solvent increases the fibers maybegin to swell, gel, and/or dissolve. Accordingly, the temperature ofthe reaction can be selected in combination with the solvent such thatthe fiber will remain insoluble and will not decompose. In embodiments,the method further comprises heating the mixture of the fiber and thehydrolysis agent solution.

The selection of the hydrolysis agent can affect the rate of thehydrolysis reaction. Thus, the hydrolysis agent can be selected incombination with the reaction time and temperature to provide a desiredincrease in the degree of hydrolysis of the polymer that makes up thefiber, e.g., a copolymer (or modified copolymer) having vinyl acetateand vinyl alcohol moieties. In embodiments wherein the hydrolysis occursby acid or base catalyzed transesterification of an ester or amide, therate of the reaction can be modified based on the nucleophilic strengthof the hydrolysis agent and, as a secondary factory, the solubility ofthe hydrolysis agent in the solvent of the hydrolysis agent solution. Inembodiments wherein the hydrolysis occurs by reduction of a functionalgroup to an —OH moiety, the rate of the reaction can be modified basedon the reducing strength of the hydrolysis agent and, as a secondaryfactor, the solubility of the hydrolysis agent in the solvent of thehydrolysis agent solution.

The hydrolysis agent can be any agent that can hydrolyze or reduce afunctional group on the polymer backbone to an —OH moiety, and/orcatalyze same. Non-limiting examples of hydrolysis agents include, butare not limited to, a metallic hydroxide, a metal hydride, a sulfite,sulfur dioxide, a dithionate, a thiosulfate, a hydrazine, oxalic acid,formic acid, ascorbic acid, dithiothreitol, a phosphite, ahypophosphite, phosphorous acid, sulfuric acid, sulphonic acid,hydrochloric acid, ammonium hydroxide, water, and combinations thereof.In embodiments, the hydrolysis agent comprises a metallic hydroxide, ametal hydride, a sulfite, sulfur dioxide, a dithionate, a thiosulfate, ahydrazine, oxalic acid, formic acid, ascorbic acid, dithiothreitol, aphosphite, a hypophosphite, phosphorous acid, sulfuric acid, sulphonicacid, hydrochloric acid, ammonium hydroxide, water, or a combinationthereof. In embodiments, the hydrolysis agent comprises a metallichydroxide, a metal hydride, a sulfite, a sulfur dioxide, a dithionate, athiosulfate, a hydrazine, oxalic acid, formic acid, ascorbic acid,dithiothreitol, a phosphite, a hypophosphite, phosphorous acid, sulfuricacid, sulphonic acid, hydrochloric acid, ammonium hydroxide, or acombination thereof. In embodiments, the hydrolysis agent comprises ametallic hydroxide, a metal hydride, a sulfite, a sulfur dioxide, adithionate, a thiosulfate, a hydrazine, oxalic acid, formic acid,ascorbic acid, dithiothreitol, a phosphite, a hypophosphite, phosphorousacid, ammonium hydroxide, or a combination thereof. In embodiments, thehydrolysis agent comprises a metallic hydroxide, ammonium hydroxide, ora combination thereof. In embodiments, the hydrolysis agent comprises ametallic hydroxide. In embodiments, the metallic hydroxide hydrolysisagent comprises an alkali metal hydroxide, an alkaline earth metalhydroxide, a main group metal hydroxide, or a combination thereof. Inembodiments, the metallic hydroxide hydrolysis agent comprises sodiumhydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide,trialkyltin hydroxide, or a combination thereof. In embodiments, themetallic hydroxide hydrolysis agent comprises sodium hydroxide,potassium hydroxide, or a combination thereof. In embodiments, themetallic hydroxide hydrolysis agent comprises sodium hydroxide.

In general, as the concentration of hydrolysis agent in the hydrolysisagent solution increases, the rate of reaction will increase. Thus, theconcentration of the hydrolysis agent can be selected in combinationwith the reaction time, reaction temperature, and selection of thehydrolysis agent to provide a desired increase in the degree ofhydrolysis of the polymer that makes up the fiber, e.g., copolymer ofvinyl acetate and vinyl alcohol. In general, the concentration of thehydrolysis agent in the hydrolysis solution can be any concentration.Typically, the concentration will be selected such that all of thehydrolysis agent provided is in solution. In embodiments, the hydrolysisagent can be provided in an amount of about 0.2% to about 75% (w/w)based on the weight of the solvent, for example, about 0.2% to about75%, about 0.2% to about 50%, about 0.2% to about 25%, about 0.5% toabout 20%, about 1% to about 18%, about 2% to about 16%, about 5% toabout 15%, about 8% to about 12%, or about 10%. In embodiments, thehydrolysis agent is provided in an amount of about 0.2% to about 25%(w/w), based on the weight of the solvent. In embodiments, thehydrolysis agent is provided in an amount of about 2% to about 25%(w/w), based on the weight of the solvent. In embodiments, thehydrolysis agent is provided in an amount of about 5% to about 15%(w/w), based on the weight of the solvent.

The solvent of the hydrolysis agent solution can generally be anysolvent in which the hydrolysis agent is soluble and the fiber to betreated is insoluble at the temperature at which the treatment takesplace for the duration of contact of the fiber with the solvent. Inembodiments, the fiber is insoluble in the solvent prior to treatment.In embodiments, the fiber is insoluble in the solvent during treatment.In embodiments, the fiber is insoluble in the solvent after treatment.In general, the solvent can be selected in combination with the reactiontime, reaction temperature, selection of the hydrolysis agent andconcentration thereof to provide a desired increase in the degree ofhydrolysis of the polymer that makes up the fiber, e.g., copolymer ofvinyl acetate and vinyl alcohol. As the polarity of the solventincreases, the diffusion of the solvent into the polymer matrix of thefiber generally increases, resulting in an increase in the diffusion ofthe hydrolysis agent into the polymer matrix. Without intending to bebound by theory, it is believed that as the polarity of the solventincreases, the degree of hydrolysis of the inner/core section of thefiber can increase, such that the degree of hydrolysis can be increasedacross a transverse cross-section of the fiber. Further, withoutintending to be bound by theory, as the polarity of the solventdecrease, the diffusion of the solvent into the polymer matrix of thefiber generally decreases, such that the degree of hydrolysis can beincreased only at the polymer at a portion of thesurface/exterior/sheath/shell of the fiber. Hydrolysis of the polymer ofthe fiber at a portion of the surface/exterior/sheath/shell of the fiberalso results in an average increase in the degree of hydrolysis across atransverse cross-section of the fiber. Further, without intending to bebound by theory, a combination of solvents can be used to provide adiffusion controlled radiant gradient of the degree of hydrolysis of thepolymers of the treated fiber.

In embodiments, the solvent for the hydrolysis agent solution can becharacterized by the Hansen Solubility Parameter (HSP). Withoutintending to be bound by theory, it is believed that the three HSPvalues, dispersion, molar volume, and hydrogen-bonding, are indicatorsof miscibility and, thus, solvation or swelling of polyvinyl alcohol bya particular solvent and further that it is believed hydrogen bonding isthe largest predictor of these expected behavior, the summation of allthe parameters, H_(total), is also predictive. In general, when the HSPvalues of the solvent are less than the HSP values of the polyvinylalcohol, the more dissimilar the HSP values are between the solvent andthe polyvinyl alcohol, the lower the diffusivity of the solvent into thepolyvinyl alcohol. Without intending to be bound by theory, it isbelieved that when the H_(total) value of the solvent is about 4 toabout 15 units lower than the H_(total) value of the polyvinyl alcohol,the rate of solvent uptake and diffusivity of the solvent into thepolyvinyl alcohol is such that a gradient of solvent uptake and, thus,hydrolysis agent uptake, will occur, providing a gradient in the degreeof hydrolysis of the fiber across a transverse cross section with ahigher degree of hydrolysis at a surface region, relative to an inner,core region. Without intending to be bound by theory, it is believedthat when the H_(total) value of the solvent is about 4 to about 15units higher than the H_(total) value of the polyvinyl alcohol, the rateof solvent uptake and diffusivity of the solvent into the polyvinylalcohol is such that solvent uptake and, thus, hydrolysis agent uptake,will occur quickly providing a uniform degree of hydrolysis across atransverse cross-section of the polyvinyl alcohol fiber. Further,without intending to be bound by theory, it is believed that when theH_(total) value of the solvent is more than 15 units lower than that ofthe polyvinyl alcohol of the fiber the diffusivity will be limited suchthat only an outer surface of the fiber will be treated with thehydrolysis agent and when the H_(total) value of the solvent is morethan 15 units higher than that of the polyvinyl alcohol of the fiber,the solvent will dissolve the polyvinyl alcohol of the fiber.

In embodiments, the solvent comprises a polar solvent. In embodiments,the solvent comprises octanol, heptanol, hexanol, pentanol, butanol,propanol, tetrahydrofuran, dichloromethane, acetone, ethanol,N-methylpyrrolidone, methanol, acetonitrile, ethylene glycol,N,N-dimethylformamide, glycerol, dimethyl sulfoxide, formic acid, water,or a combination thereof. In embodiments, the solvent comprisesn-octanol, n-heptanol, n-hexanol, n-pentanol, n-butanol, isobutanol,sec-butanol, tert-butanol, n-propanol, isopropanol, acetone, ethanol,N-methylpyrrolidone, methanol, acetonitrile, N,N-dimethylformamide,dimethyl sulfoxide, formic acid, water, or a combination thereof. Inembodiments, the solvent comprises n-propanol, acetone, ethanol,N-methylpyrrolidone, methanol, acetonitrile, N,N-dimethylformamide,dimethyl sulfoxide, formic acid, water, or a combination thereof. Inembodiments, the solvent comprises an alcohol that is a liquid under theadmixing conditions. In embodiments, the solvent comprises methanol. Inembodiments, the solvent comprises methanol and at least one additionalsolvent. In embodiments, the solvent comprises methanol and water. Inembodiments, the solvent comprises at least one of butanol, pentanol,hexanol, heptanol, and octanol in combination with water. Inembodiments, the solvent comprises DMSO and water. In embodiments, thesolvent comprises DMSO and water and the DMSO and water are provided ina weight ratio of about 40/60 to 80/20. Without intending to be bound bytheory, it is believed that as the amount of water increases above 60%or the amount of DMSO increases above about 80%, the interaction of therespective solvents with polyvinyl alcohol increases, resulting inincreased swelling and gelling of the polymer.

In embodiments, the solvent comprises a nonpolar solvent. Inembodiments, the solvent comprises hexanes, cyclohexane, methylpentane,pentane, cyclopropane, dioxane, benzene, pyridine, xylene, toluene,diethyl ether, chloroform, or a combination thereof.

In embodiments, the solvent comprises a mixture of a first solvent and asecond solvent. In embodiments, the first solvent comprises a polarsolvent and the second solvent comprises a nonpolar solvent. Inembodiments, the first solvent has a first dielectric constant and thesecond solvent has a second dielectric constant and the dielectricconstant of the first solvent is higher than the dielectric constant ofthe second solvent. In embodiments, the first dielectric constant is 5or less, 4 or less, 3 or less, or 2 or less. In embodiments, the seconddielectric constant is greater than 5, greater than 7.5, greater than10, greater than 15, greater than 18, greater than 20, greater than 25,or greater than 30. In embodiments, the difference between the firstdielectric constant and the second dielectric constant is at least 3, atleast 5, at least 8, or at least 10. In embodiments, wherein the solventcomprises a mixture of a first solvent and a second solvent, the firstsolvent and the second solvent can be provided in any ratio providedthat the hydrolysis agent is soluble in the mixture and the fiber is notsoluble in the mixture prior to treatment, during treatment, and aftertreatment. In embodiments, the first solvent and second solvent can beprovided in a weight ratio of about 99/1 to about 1/99, about 95/5 toabout 5/95, about 90/10 to 10/90, about 85/15 to about 15/85, about80/20 to about 20/80, about 75/25 to about 25/75, about 70/30 to about30/70, about 65/35 to about 35/65, about 60/40 to about 40/60, about55/45 to about 45/55, or about 50/50.

In some embodiments, the first solvent is methanol and the secondsolvent is hexane. Methanol and hexane can be in any suitable ratio byweight or by volume. For example, a solvent including 10% of methanoland 90% hexane by weight catalyzes secondary saponification in at leastone portion of a fiber comprising the polymer as described herein.

In embodiments, the methods of the disclosure further include admixingan activator with the fiber and the hydrolysis agent solution. Theactivator can be any additive that facilitates the treatment of thefiber by the hydrolysis agent. The activator can include a catalyst forreducing the activation energy of the reaction between the polymer ofthe fiber and the hydrolysis agent or a compound that facilitatesdiffusion of the hydrolysis agent into the polymer matrix, for example.

The reaction conditions can also be selected to design and control thesolubility mechanism and/or absorption capacity and retention of thetreated fiber. For example, the reaction conditions can be selected toprovide a fiber having a transverse cross-section characterized by (a) acore-sheath structure wherein the polymer of the sheath has a greaterdegree of hydrolysis than the polymer of the core (FIG. 2A), (b) anincreasing radial gradient in the degree of hydrolysis of the polymerfrom an interior region to a surface region (FIG. 2B; FIG. 3 ), or (c) aconsistent degree hydrolysis across the transverse cross-section (FIG.2C) and the resulting fibers can have different solubility mechanisms(for example, immediate release, delayed release, or triggered release)and/or absorption capacity and retention properties. Reaction conditionsthat can be modified to provide a predetermined fiber structure includethe selection of the hydrolysis agent, selection of the concentration ofthe hydrolysis agent in the hydrolysis agent solution, reaction(admixing) time, reaction (admixing) temperature, selection of solventfor the hydrolysis agent solution, and optional inclusion of anactivator.

A fiber having a core-sheath structure can be prepared by treating afiber having a polymer having a degree of hydrolysis of less than 100%as described herein with a hydrolysis agent solution under conditionssufficient to minimize the radial diffusion of the solvent and thehydrolysis agent into an inner core region of the fiber. Diffusion ofthe solvent and hydrolysis agent into an inner core region of the fibercan be minimized, for example, by selecting a short reaction time, a lowreaction temperature, and/or including a nonpolar solvent. Inembodiments, the admixing of the methods of the disclosure is performedunder conditions sufficient to provide a polyvinyl alcohol fiber havinga transverse cross-section characterized by a core-sheath structure,wherein the polymer of the sheath has a greater degree of hydrolysisthan the polymer of the core. In embodiments, the conditions sufficientto provide a polyvinyl alcohol fiber having a transverse cross-sectioncharacterized by a core-sheath structure, wherein the polymer of thesheath has a greater degree of hydrolysis than the polymer of the corecomprises including in the hydrolysis agent solution a solvent having adielectric constant of 20 or less, 18 or less, 14 or less, or 10 orless. In embodiments, the conditions sufficient to provide a polyvinylalcohol fiber having a transverse cross-section characterized by acore-sheath structure, wherein the polymer of the sheath has a greaterdegree of hydrolysis than the polymer of the core comprises admixing thefiber and the hydrolysis agent solution at a temperature in a range ofabout 10° C. to about 30° C., about 10° C. to about 25° C., or about 15°C. to about 25° C. In embodiments, the conditions sufficient to providea polyvinyl alcohol fiber having a transverse cross-sectioncharacterized by a core-sheath structure, wherein the polymer of thesheath has a greater degree of hydrolysis than the polymer of the corecomprises admixing the fiber and the hydrolysis agent solution for atime of about 2 minutes to about 6 hours, about 2 minutes to about 4hours, about 5 minutes to about 3 hours, about 10 minutes to about 2hours, or about 15 minutes to about 1 hour. In embodiments, theconditions sufficient to provide a polyvinyl alcohol fiber having atransverse cross-section characterized by a core-sheath structure,wherein the polymer of the sheath has a greater degree of hydrolysisthan the polymer of the core comprises including in the hydrolysis agentsolution a solvent having a dielectric constant of 20 or less, 18 orless, 14 or less, or 10 or less, admixing the fiber and the hydrolysisagent solution at a temperature in a range of about 10° C. to about 30°C., about 10° C. to about 25° C., or about 15° C. to about 25° C., andadmixing the fiber and the hydrolysis agent solution for a time of about2 minutes to about 6 hours, about 2 minutes to about 4 hours, about 5minutes to about 3 hours, about 10 minutes to about 2 hours, or about 15minutes to about 1 hour. Such fibers having a transverse cross-sectioncharacterized by a core-sheath structure wherein the polymer of thesheath has a greater degree of hydrolysis than the polymer of the corecan provide delayed release properties of an active provided in theinterior of the fiber, triggered release of an active provided in theinterior of the fiber, increased absorbance relative to a fiber having aconsistent degree of hydrolysis across a transverse cross-section,and/or improved retention of absorbed fluids relative to a fiber havinga consistent degree of hydrolysis across a transverse cross-section.

As used herein and unless specified otherwise, “delayed release” of anactive from a fiber means that the entirety of the active is notimmediately released from the fiber when contacted with a solvent(usually water) under the conditions of an end use application of thefiber. For example, a fiber containing an active and used in a laundryapplication may not immediately release the entirety of the active underwash conditions. Rather, the active can diffuse from the fiber overtime. As used herein and unless specified otherwise, “triggered release”of an active from a fiber means that none of the active is released fromthe fiber until a trigger condition is met. For example, a fibercontaining an active and used in a laundry application may not releasethe active until the wash water reaches a predetermined temperatureand/or pH.

Trigger conditions can include, but are not limited to, temperature, pH,UV/VIS radiation, IR radiation, presence of ions, presence of catalysts,or a combination thereof.

Without intending to be bound by theory, it is believed that fibershaving a transverse cross-section characterized by a core-sheathstructure wherein the polymer of the sheath has a greater degree ofhydrolysis than the polymer of the core can have increased fluidabsorption and/or retention relative to a fiber having a consistentdegree of hydrolysis across a transverse cross-section because thepresence of the sheath allows the core to swell when in contact withfluid, allowing increased absorbance capacity, without decomposition ofthe fiber, and will retain the fluid until the fiber is contacted with atriggering condition, such as immersion in hot water.

As the thickness of the sheath structure increases, the stability of afiber having a core swollen and saturated with a fluid increases but theamount of polymer available in the core for absorbing a fluid decreases.The thickness of the sheath is can be controlled by controlling thediffusion of the hydrolysis agent into the polymer structure of thefiber. It will be understood that because treatment of the innerportions of the fiber is diffusion controlled, the sheath may have avariation in thickness around a perimeter of the fiber and the innerportion of the sheath may have a degree of hydrolysis that is less thanthe degree of hydrolysis of the polymer at the exterior surface of thesheath but greater than the degree of hydrolysis of the polymer at thecenter of the fiber. Thus in some embodiments, the transversecross-section of the fiber can be characterized by a core-sheathstructure and can also be characterized as having an increasing gradientfrom an inner portion of the fiber to an exterior portion of the fiber.

A fiber having a transverse cross-section characterized by an increasingradial gradient structure can be prepared by treating a fiber having apolymer such as a polyvinyl alcohol copolymer or a modified copolymerhaving a degree of hydrolysis of less than 100% with a hydrolysis agentsolution under conditions sufficient to modify the radial diffusion ofthe solvent and the hydrolysis agent into an inner region of the fiber.In embodiments, a polyvinyl alcohol fiber having a transversecross-section characterized by an increasing radial gradient structurefrom an inner region to an exterior region can be prepared usingmultiple solvents having different rates of diffusion (concurrently orstep-wise), changing the temperature during admixing to modify the rateof diffusion of the solvent and hydrolysis agent into the fiber, and/orselecting the reaction time such that it is long enough to allow somehydrolysis agent diffuses into the inner region to modify the degree ofhydrolysis of the polymer but is not so long as to allow the polymer ofthe inner portion to hydrolyze to the same extent as the polymer of theexterior/surface portion. In embodiments, the admixing of the methods ofthe disclosure is performed under conditions sufficient to provide afiber having a transverse cross-section characterized by an increasinggradient in the degree of hydrolysis of the polymer from an interiorregion of the fiber to a surface region of the fiber. Such fibers havinga transverse cross-section characterized by an increasing gradient ofdegree of hydrolysis can provide delayed release properties of an activeprovided in the interior of the fiber, triggered release of an activeprovided in the interior of the fiber, increased absorbance relative toa fiber having a consistent degree of hydrolysis across a transversecross-section, and/or improved retention of absorbed fluids.

Fibers having a transverse cross-section characterized by a core-sheathstructure and/or an increasing radial structure can have active agentsloaded in the core/inner regions. Actives can be loaded to thecore/inner regions by contacting a fiber with a solution of an activeagent and allowing the active agent solution to diffuse into the polymerstructure, resulting in the core/inner regions of the fiber to absorbthe active agent solution and swell. The active agent can be any activeagent disclosed herein that is soluble in the active agent solutionsolvent. The solvent can be any solvent disclosed herein. Withoutintending to be bound by theory, it is believed that as the polarity ofthe solvent increases, the rate of diffusion to the core/inner regionsof the fiber increases. An exemplary solvent is water provided that thewater of the active agent solution is maintained at a temperature belowthe solubility temperature of the polymer that makes up the core/innerregion of the fiber and the sheath/shell/exterior region of the fiber.

A fiber having a transverse cross-section characterized by the polymerhaving the same degree of hydrolysis across (throughout) the transversecross-section can be prepared by treating a fiber having a polymer suchas a polyvinyl alcohol copolymer or a modified copolymer having a degreeof hydrolysis of less than 100% with a hydrolysis agent solution underconditions sufficient to maximize the radial diffusion of the solventand the hydrolysis agent into an inner core region of the fiber.Diffusion of the solvent and hydrolysis agent into an inner core regionof the fiber can be maximized, for example, by selecting a long reactiontime, a high reaction temperature, and/or including a highly polarsolvent. In embodiments, the admixing of the methods of the disclosureis performed under conditions sufficient to provide a fiber having atransverse cross-section characterized by the polymer having the samedegree of hydrolysis across the transverse cross-section.

Without intending to be bound by theory, it is believed that for a fibercomprising a polyvinyl alcohol copolymer or a modified copolymer as thefiber forming material, the average degree of hydrolysis across atransverse cross-section of the fiber informs on the solubilitymechanism of the fiber and the absorbance capacity of the fiber. Inparticular, without intending to be bound by theory, it is believed thatas the average degree of hydrolysis across the transverse cross-sectionof the fiber increases the longer the fiber is expected to survive inwater as the temperature of the water increases. Additionally, withoutintending to be bound by theory, it is believed that as the averagedegree of hydrolysis across the transverse cross-section of the fiberincreases, the absorbance capacity of the fiber decreases.

Advantageously, as the degree of hydrolysis of the polymer at thesurface region of a fiber increases, relative to the degree ofhydrolysis of the polymer in the inner region of the fiber, the bulksolubility of the fiber decreases, allowing for more precise tuning ofthe solubility parameters of the fibers and different solubilitycharacteristics of the fibers, relative to merely selecting a fiberhaving a consistent degree of hydrolysis throughout the fiber.

The disclosure further provides a method of treating a fiber comprisinga hydrolyzable polymer, comprising contacting a surface of a fibercomprising a hydrolyzable polymer such as a polymer comprising at leastone of a vinyl acetate moiety or a vinyl alcohol moiety as describedherein (e.g., a polyvinyl alcohol copolymer or a modified copolymer)having a degree of hydrolysis less than 100% with a hydrolysis agentsolution to increase the degree of hydrolysis of the hydrolyzablepolymer in a region of the fiber comprising at least the surface of thefiber. In embodiments, the contacting can be by immersion, spraying,transfer coating, wicking, foaming, brushing, rolling, humidification,vapor deposition, printing, or a combination thereof. The hydrolyzablepolymer can be any hydrolyzable polymer disclosed herein. Inembodiments, the hydrolyzable polymer comprises a polymer comprising atleast one of a vinyl acetate moiety or a vinyl alcohol moiety, which canbe selected from the group consisting of a polyvinyl acetatehomopolymer, a polyvinyl alcohol copolymer, a modified polyvinyl alcoholcopolymer, or a combination thereof. The hydrolysis agent solution caninclude any hydrolysis agent disclosed herein and any solvent disclosedherein. In embodiments, the method can further comprise contacting thesurface of the fiber with the hydrolysis agent solution after formationof the fiber as part of a continuous inline process. For example, thefiber can be formed from a polymer mixture at a first station and thentransferred to a second station where the surface of the fibers can betreated. In another example, the fiber can treated on an apparatusincluding a polyvinyl alcohol fiber supply station, a polyvinyl alcoholfiber treating station, and a polyvinyl alcohol fiber collectionstation. In embodiments, the fiber is in motion during the contacting ofthe surface of the fibers. In embodiments, the contacting the surface ofthe fiber with the hydrolysis agent solution is performed in a batch bybatch process. For example, the fibers can be prepared in bulk and canbe treated with the hydrolysis agent prior to formation of the fibersinto nonwoven webs. In embodiments, the fiber comprises staple fiber,staple yarn, fiber fill, needle punch fabrics, bonding fibers, or acombination thereof. In embodiments, the fiber comprises staple fiber.In embodiments, the method further comprises washing and drying thefiber after contacting the surface of the fiber with the hydrolysisagent solution. The washing can be by rinsing the fiber with anon-solvent. The drying the fiber can be by air jet drying, agitating,vortexing, or centrifuging.

Although the methods disclosed herein describe treating a fiber suchthat the degree of hydrolysis of at least a portion of the polymer thatmakes up the fiber is increased, it will be understood that the fiberscan be treated such that the degree of hydrolysis of at least a portionof the polymer that makes up the fiber is decreased. Thus, thedisclosure further provides methods of acylation at least a portion of apolyvinyl alcohol polymer comprising admixing a fiber comprising apolyvinyl alcohol polymer with an acylation agent solution to decreasethe degree of hydrolysis of at least a portion of the polyvinyl alcoholpolymer in the fiber.

The admixing conditions can be any of the conditions described hereinfor admixing the fiber with the hydrolysis agent solution. Instead of ahydrolysis agent, the acylation agent solution will include an acylationagent. The admixing conditions can be selected to provide apredetermined degree of hydrolysis or predetermined degree of hydrolysisdecrease as described herein for the methods for increasing the degreeof hydrolysis. Fibers treated with the acylation agent solution can havea transverse cross-section characterized by a core-sheath structure,wherein the polymer of the sheath has a smaller degree of hydrolysisthan the polymer of the core, a transverse cross-section characterizedby a decreasing gradient in the degree of hydrolysis of the polymer froman interior region to a surface region, or a transverse cross-sectioncharacterized by the polymer having the same degree of hydrolysis acrossthe cross-section.

The acylation agent can be any agent that when contacted with a polymerhaving a pendant hydroxyl (—OH) or amine (—NR₂) converts a hydrogen ofthe pendant hydroxyl or amine to an acyl group (R—C(O)—). Suitableacylation agents include, but are not limited to aldehydes, acylanhydrides, acyl chlorides, and acyl-coenzymes. In embodiments, theacylation agent comprises an aldehyde in the presence of an acidcatalyst such as hydrochloric acid. In embodiments, the acylation agentcomprises acetic anhydride and/or acetyl chloride, optionally in thepresence of a tertiary or aromatic amine base. In embodiments theacylation agent comprises acetyl coenzyme A (acetyl-CoA) in the presenceof the enzyme acetyltransferases.

The disclosure provides a fiber treated according to the methods of thedisclosure.

The disclosure provides a fiber having a surface region and an interiorregion, the fiber comprising a hydrolyzable polymer, the fiber having atransverse cross-section characterized by the hydrolyzable polymer ofthe surface region having a greater degree of hydrolysis than thehydrolyzable polymer of the interior region. In embodiments, thedisclosure provides a fiber having a surface region and an interiorregion, the fiber comprising a polymer comprising at least one of avinyl acetate moiety or a vinyl alcohol moiety, the fiber having atransverse cross-section characterized by the polymer of the surfaceregion having a greater degree of hydrolysis than the polymer of theinterior region.

The fiber of the disclosure can have a transverse cross-section of thefiber characterized by an increasing gradient in the degree ofhydrolysis of the hydrolyzable polymer from the interior region to thesurface region. In embodiments, the fiber of the disclosure can have atransverse cross-section of the fiber characterized by an increasinggradient in the degree of hydrolysis of the polymer from the interiorregion to the surface region.

As shown in FIG. 3 , the disclosure provides a fiber comprising atransverse cross-section characterized by a core-sheath structure, thefiber comprising a first, core region (denoted 401 in FIG. 3 ),comprising a hydrolyzable polymer having a degree of hydrolysis lessthan 100%, and a second, sheath region (denoted 402 in FIG. 3 ),comprising a hydrolyzable polymer having a degree of hydrolysis greaterthan the hydrolyzable polymer of the first region. In embodiments, thefiber can comprise a transverse cross-section characterized by acore-sheath structure, the fiber comprising a first, core region,comprising a polyvinyl alcohol polymer having a degree of hydrolysisless than 100%, and a second, sheath region, comprising a polymer havinga degree of hydrolysis greater than the polymer of the first region. Inembodiments, the fiber further comprises a third, intermediate region(denoted 403 in FIG. 3 ), disposed between the first and second regionsand comprising a hydrolyzable polymer having a degree of hydrolysisgreater than the hydrolyzable polymer of the first region and less thanthe hydrolyzable polymer of the second region. In embodiments, thehydrolyzable polymer of the first, second, and third regions cancomprise a polyvinyl alcohol polymer. In embodiments, the fiber cancomprise a plurality of third, intermediate regions (denoted 403A, 403Bin FIG. 3 ), disposed between the first and second regions, thetransverse cross-section of the fiber characterized by an increasinggradient in the degree of hydrolysis of the hydrolyzable polymer fromthe first region to the second region. In embodiments, the plurality ofthird, intermediate regions, can include a polyvinyl alcohol polymer,the transverse cross-section of the fiber characterized by an increasinggradient in the degree of hydrolysis of the polymer from the firstregion to the second region.

In embodiments, the fibers of the disclosure can have a difference inthe degree of hydrolysis of the polymers in the first and second regionsof about 1%, about 2%, about 3%, about 5%, about 7%, about 10%, about11%, about 12%, about 15%, about 18%, about 20%, about 23%, about 25%,about 27%, or about 29%, for example, in a range of 1% to 29%, about 1%to about 25%, about 1% to about 20%, about 2% to about 18%, about 2% toabout 15%, about 3% to about 12%, or about 3% to about 11%. Inembodiments, the transverse cross-section of the fiber can becharacterized by a mean radius and the second region can comprise about0.5% of the mean radius of the fiber, for example, about 1%, about 2%,about 3%, about 5%, about 7%, about 9%, about 10%, about 12%, about 15%,about 20%, about 25%, about 50%, about 75%, about 80%, about 85%, about90%, about 92%, about 94%, about 96%, or about 98%, for example in arange of about 1% to about 98%, about 1% to about 90%, about 1% to about75%, about 1% to about 50%, about 1% to about 25%, about 1% to about 20%about 1% to about 15%, about 1% to about 12% about 1% to about 10%,about 1 % to about 8%, about 1% to about 6%, about 1% to about 5%, about1% to about 4%, about 2% to about 25%, about 4% to about 25%, about 6%to about 35%, or about 8% to about 20%.

In embodiments, the hydrolyzable polymers in the first, second, andoptional third regions have the same degree of polymerization. Inembodiments, the hydrolyzable polymers in the first, second, andoptional third regions comprise polyvinyl alcohol polymers having thesame degree of polymerization. In embodiments, the hydrolyzable polymersin the first, second, and optional third regions comprise modifiedpolyvinyl alcohol polymers having the same degree of modification.

Although the fibers disclosed herein having a transverse cross-sectioncharacterized by a core-sheath structure or gradient degree ofhydrolysis are described as having a greater degree of hydrolysis in thesheath and/or surface region of the fiber, it will be understood thatthe fibers can be prepared (i.e., with an acylation agent) such that thedegree of hydrolysis in the polymer of the sheath and/or surface regionof the fiber is less than the degree of hydrolysis of the polymer of thecore and/or inner surface region. Thus, the disclosure further providesa fiber having a surface region and an interior region, the fibercomprising a hydrolyzable polymer, the fiber having a transversecross-section characterized by the hydrolyzable polymer of the surfaceregion having a lesser degree of hydrolysis than the hydrolyzablepolymer of the interior region. In embodiments, the disclosure providesa fiber having a surface region and an interior region, the fibercomprising a polyvinyl alcohol polymer, the fiber having a transversecross-section characterized by the polyvinyl alcohol polymer of thesurface region having a lesser degree of hydrolysis than the polyvinylalcohol polymer of the interior region.

The fiber of the disclosure can have a transverse cross-section of thefiber characterized by a decreasing gradient in the degree of hydrolysisof the hydrolyzable polymer from the interior region to the surfaceregion. In embodiments, the fiber of the disclosure can have atransverse cross-section of the fiber characterized by a decreasinggradient in the degree of hydrolysis of the polymer from the interiorregion to the surface region.

In the fiber having a surface region and an interior region provided inthe present disclosure, the polymer in the interior region has a firstdegree of hydrolysis and the polymer in the surface region has a seconddegree of hydrolysis greater than the first degree of hydrolysis. Insome embodiments, the first degree of hydrolysis is in a range of fromabout 79% to about 96% and the second degree of hydrolysis is in a rangeof from about 88% to 100%, for example, from about 90% to 100%, fromabout 88% to 99%, or from about 90% to about 99%. In some embodiments,the first degree of hydrolysis is in a range of from about 79% to about92% and the second degree of hydrolysis is in a range of from about 88%to about 96%.

The fiber has a dissolution time of less than 200 seconds in water at23° C. The fiber has a shrinkage along a longitudinal axis of the fiberin a range of from 20% to 70% while contacting water at a temperature ina range of from 10° C. to 23° C. In embodiments, the polymer in theinterior region has a glass transition temperature (T_(g)) in a range offrom about 72° C. to about 72.9° C. and the polymer in the surfaceregion has a T_(g) in a range of from about 73° C. to about 85° C.

In some embodiments, the fiber provided in the present disclosure has alongitudinal axis and a transverse cross-section perpendicular to thelongitudinal axis of the fiber. The fiber further has a core and sheathstructure along at least a portion of the longitudinal axis. The fibercomprises a core region of the core and sheath structure comprising apolymer comprising at least one of a vinyl acetate moiety or a vinylalcohol moiety having a first degree of hydrolysis less than 100%.

The fiber has a sheath region of the core and sheath structure disposedradially outward from the core region in the transverse cross-section.The sheath region comprises the polymer comprising at least one of avinyl acetate moiety or a vinyl alcohol moiety having a second degree ofhydrolysis greater than the first degree of hydrolysis. As describedherein, in embodiments, the polymer comprising at least one of a vinylacetate moiety or a vinyl alcohol moiety comprises a polyvinyl alcoholhomopolymer, a polyvinyl acetate homopolymer, a vinyl acetate and vinylalcohol copolymer, a modified polyvinyl alcohol copolymer, orcombinations thereof. A difference between the first degree ofhydrolysis and the second degree of hydrolysis is at least 1%. Thedifference between the first degree of hydrolysis and the second degreeof hydrolysis may be in a range of 1% to 29%. The first and the seconddegrees of hydrolysis may be within the ranges as described above. Forexample, with the sheath region having a second degree of hydrolysis ina range of from about 88% to about 96%, the fiber has a dissolution timeof less than 200 seconds in water at 23° C., the fiber has a dryingshrinkage in a range of from about 20% to about 70% after soaking inwater at a temperature in a range of from 10° C. to 23° C., and thepolymer in the sheath region has a glass transition temperature in arange of from about 73° C. to about 85° C. The core and sheath (orshell) structure may include at least one intermediate layer asdescribed above.

The present disclosure also provides a fiber comprising a first regionand a second region. The first region comprises a polymer comprising atleast one of a vinyl acetate moiety or a vinyl alcohol moiety having afirst degree of hydrolysis less than 100%. The second region comprisesthe polymer comprising at least one of a vinyl acetate moiety or a vinylalcohol moiety having a second degree of hydrolysis greater than thefirst degree of hydrolysis. In embodiments, such a polymer comprises apolyvinyl alcohol homopolymer, a polyvinyl acetate homopolymer, a vinylacetate and vinyl alcohol copolymer, a modified polyvinyl alcoholcopolymer, or a combination thereof. The fiber has a longitudinal axis.The first region forms a core region of the fiber along the longitudinalaxis and the second region forms a sheath region of the fibersurrounding at least a portion of the core region. The fiber has atransverse cross-section perpendicular to the longitudinal axis.

The fiber may further comprise an intermediate region disposed betweenthe first region and the second region in the transverse cross-section.The intermediate region comprises the polymer having a third degree ofhydrolysis greater than the first degree of hydrolysis and less than thesecond degree of hydrolysis. The fiber has a transverse cross-sectionperpendicular to the longitudinal axis. The fiber may further comprise aplurality of intermediate regions comprising the polymer and disposedbetween the first region and the second region, and the transversecross-section has an increasing gradient in a degree of hydrolysis fromthe first region to the second region. As described above, thedifference between the first degree of hydrolysis and the second degreeof hydrolysis is at least 1%; for example, in a range of from 1% to 29%.The polymer in each of the first region, the second region, and thethird region may have a same degree of polymerization, for example, thepolymer comprises a modified polyvinyl alcohol polymer having a samedegree of modification.

Nonwoven Webs

The nonwoven webs of the disclosure are generally sheet-like structureshaving two exterior surfaces, the nonwoven webs including a plurality offibers. As used herein, and unless specified otherwise, the “exteriorsurface” of a nonwoven web refers to the faces of the sheet-likestructure, denoted 100 and 101 in FIG. 7 . A nonwoven web generallyrefers to an arrangement of fibers bonded to one another, wherein thefibers are neither woven nor knitted. In general, the plurality offibers can be arranged in any orientation. In embodiments, the pluralityof fibers are arranged randomly (i.e., do not have an orientation). Inembodiments, the plurality of fibers are arranged in a unidirectionalorientation. In embodiments, the plurality of fibers are arranged in abidirectional orientation. In some embodiments, the plurality of fibersare multi-directional, having different arrangements in different areasof the nonwoven web. In embodiments, the nonwoven web can include asingle type of water-soluble fiber. In embodiments, the nonwoven web caninclude a single type of water-insoluble fiber. In embodiments, thenonwoven web can include a single type of water-soluble fiber and one ormore different types of water-insoluble fibers. In embodiments, thenonwoven web can include one or more different types of water-solublefibers and one or more different types of water-insoluble fibers. Inembodiments, the nonwoven web can consist of or consist essentially ofwater-soluble fibers. In embodiments, the nonwoven web can consist of orconsist essentially of water-insoluble fibers. In some embodiments, thenonwoven web can include a single type of fiber forming material (i.e.,all fibers have the same composition of fiber forming material), but caninclude fibers prepared by one or more fiber forming processes, e.g.,wet cooled gel spinning, thermoplastic fiber spinning, melt blowing,spun bonding, or a combination thereof. In some embodiments, thenonwoven web can include a single type of fiber forming material and thefibers are made from a single fiber forming process. In someembodiments, the nonwoven web can include two or more fiber formingmaterials (e.g., blends of fibers having different compositions of fiberforming materials, fibers including blends of fiber forming materials,or both) and the fibers can be prepared by one or more fiber formingprocesses, e.g., wet-cool gel spinning, thermoplastic fiber spinning,melt blowing, spun bonding, or a combination thereof. In someembodiments, the nonwoven web can include two or more fiber formingmaterials and the fibers are made from a single fiber forming process.In embodiments, the fibers of the nonwoven web can have substantiallythe same diameters or different diameters.

In embodiments wherein the nonwoven webs of the disclosure include ablend of fibers including a first fiber and a second fiber, the firstand second fibers can have a difference in length to diameter (L/Dratio, tenacity, shape, rigidness, elasticity, solubility, meltingpoint, glass transition temperature (T_(g)), fiber forming material,color, or a combination thereof.

As is well understood in the art, the term machine-direction (MD) refersto the direction of web travel as the nonwoven web is produced, forexample on commercial nonwoven making equipment. Likewise, the termcross-direction (CD) refers to the direction in the plane of the webperpendicular to the machine-direction. With respect to nonwovencomposite articles, wipes, absorbent articles or other articlecomprising a nonwoven composite article of the disclosure, the termsrefer to the corresponding directions of the article with respect to thenonwoven web used to produce the article.

The tenacity of the nonwoven web can be the same or different from thetenacity of the fibers used to prepare the web. Without intending to bebound by theory, it is believed that the tenacity of the nonwoven web isrelated to the strength of the nonwoven web, wherein a higher tenacityprovides a higher strength to the nonwoven web. In general, the tenacityof the nonwoven web can be modified by using fibers having differenttenacities. The tenacity of the nonwoven web may also be affected byprocessing. In general, water-dispersible webs of the disclosure canhave relatively high tenacities, i.e., the water-dispersible nonwovenweb is a self-supporting web that can be used as the sole material forpreparing an article and/or pouch. In embodiments, the nonwoven web is aself-supporting web. In contrast, the nonwoven webs that are preparedaccording to melt blowing, electro-spinning, and/or rotary spinningprocesses typically have low tenacities, and may not be self-supportingor capable of being used as a sole web for forming an article or pouch.Thus, in some embodiments, the nonwoven web is not self-supporting andis used in combination with a second nonwoven web and/or water-solublefilm.

In embodiments, the nonwoven webs of the disclosure can have a ratio oftenacity in the machine direction to the tenacity in the cross direction(MD:CD) of in a range of about 0.5 to about 1.5, about 0.75 to about1.5, about 0.80 to about 1.25, about 0.90 to about 1.1, or about 0.95 toabout 1.05, or about 1. In embodiments, the nonwoven webs of thedisclosure have a tenacity ratio MD:CD of about 0.8 to about 1.25. Inembodiments the nonwoven webs of the disclosure have a tenacity ratioMD:CD of about 0.9 to about 1.1. In embodiments, the nonwoven webs ofthe disclosure have a tenacity of about 1. Without intending to be boundby theory, it is believed that as the tenacity ratio MD:CD approaches 1,the durability of the nonwoven is increased, providing superiorresistance to breakdown of the nonwoven when stress is applied to thenonwoven during use, e.g., scrubbing with a flushable wipe comprising anonwoven web of the disclosure, or pulling/tugging on the nonwovencaused by movement while wearing a wearable absorbent article.

The nonwoven webs of the disclosure can have a rougher surface relativeto a water-soluble film, which provides decreased contact between asurface and the nonwoven web than between a surface and thewater-soluble film. Advantageously, this surface roughness can providean improved feel to the consumer (i.e., a cloth-like hand-feel insteadof a rubbery hand-feel), improved aesthetics (i.e., less glossy than awater-soluble film), and/or facilitate processability in preparingthermoformed, and/or vertical formed, filled, and sealed, and/ormultichamber packets which require drawing the web along a surface ofthe processing equipment/mold. Accordingly, the fibers should besufficiently coarse to provide a surface roughness to the resultingnonwoven web without being so coarse as to produce drag.

Nonwoven webs can be characterized by basis weight. The basis weight ofa nonwoven is the mass per unit area of the nonwoven. Basis weight canbe modified by varying manufacturing conditions, as is known in the art.A nonwoven web can have the same basis weight prior to and subsequent tobonding. Alternatively, the bonding method can change the basis weightof the nonwoven web. For example, wherein bonding occurs through theapplication of heat and pressure, the thickness of the nonwoven (and,thus, the area of the nonwoven) can be decreased, thereby increasing thebasis weight. Accordingly, as used herein and unless specifiedotherwise, the basis weight of a nonwoven refers to the basis weight ofthe nonwoven subsequent to bonding.

The nonwoven webs of the disclosure can have any basis weight in a rangeof about 0.1 g/m² to about 700 g/m², about 0.5 g/m² to about 600 g/m²,about 1 g/m² to about 500 g/m², about 1 g/m² to about 400 g/m², about 1g/m² to about 300 g/m², about 1 g/m² to about 200 g/m², about 1 g/m² toabout 100 g/m², about 30 g/m² to about 100 g/m², about 20 g/m² to about100 g/m², about 20 g/m² to about 80 g/m², or about 25 g/m² to about 70g/m².

In embodiments, the nonwoven web can be carded and have a basis weightof about 5 g/m² to about 15 g/m², about 7 g/m² to about 13 g/m², about 9g/m² to about 11 g/m², or about 10 g/m². In embodiments, the nonwovenweb can be carded and can have a basis weight of 30 g/m² or more, forexample in a range of 30 g/m² to about 70 g/m², about 30 g/m² to about60 g/m², about 30 g/m² to about 50 g/m², about 30 g/m² to about 40 g/m²,or about 30 g/m² to about 35 g/m². In embodiments, the nonwoven web canbe melt-spun and have a basis weight in a range of about 1 g/m² to about20 g/m², about 2 g/m² to about 15 g/m², about 3 g/m² to about 10 g/m²,about 5 g/m² to about 15 g/m², about 7 g/m²to about 13 g/m², about 9g/m² to about 11 g/m², or about 10 g/m². In embodiments, the nonwovenweb can be melt-spun and can have a basis weight of about 0.1 g/m² toabout 10 g/m², about 0.1 g/m² to about 8 g/m², about 0.2 g/m² to about 6g/m², about 0.3 g/m² to about 4 g/m², about 0.4 g/m² to about 2 g/m², orabout 0.5 g/m² to about 1 g/m².

Related to the basis weight is the fiber volume density and porosity ofa nonwoven. Nonwoven webs, as prepared and prior to bonding, generallyhave a fiber density of about 30% or less by volume, i.e., for a givenvolume of nonwoven, 30% or less of the volume is made up of the fibersand the remaining volume is air. Thus, the nonwoven webs are generallyhighly porous. Fiber volume density and porosity of the nonwoven areinversely related characteristics of a nonwoven, for example, a nonwovenhaving a fiber volume density of about 30% by volume would have aporosity of about 70% by volume. It is well understood in the art thatas the fiber volume density increases, the porosity decreases. Fibervolume density can be increased by increasing the basis weight of anonwoven, for example, by bonding through the application of heat andpressure, potentially reducing the thickness (and, thus, the volume) ofthe nonwoven. Accordingly, as used herein and unless specifiedotherwise, the fiber volume density and porosity of a nonwoven refers tothe fiber volume density and porosity of the nonwoven subsequent tobonding.

The nonwoven webs of the disclosure can have any porosity in a range ofabout 50% to about 95%, for example, at least about 50%, at least about60%, at least about 70%, at least about 75%, or at least about 80% andup to about 95%, up to about 90%, up to about 85%, up to about 80%, upto about 75%, up to about 70%, or in a range of about 50% to about 95%,about 50% to about 80%, about 50% to about 70%, about 60% to about 75%,about 60% to about 80%, about 60% to about 90%, about 75% to about 85%,about 75% to about 90%, or about 75% to about 95%.

Pore sizes can be determined using high magnification and orderedsurface analysis techniques including, but not limited toBrunauer-Emmett-Teller theory (BET), small angle X-ray scattering(SAXS), and molecular adsorption.

The nonwoven webs of the disclosure can have any thickness. Suitablethicknesses can include, but are not limited to, about 5 to about 10,000µm (1 cm), about 5 to about 5,000 µm, about 5 to about 1,000 µm, about 5to about 500 µm, about 200 to about 500 µm, about 5 to about 200 µm,about 20 to about 100 µm, or about 40 to about 90 µm, or about 50 to 80µm, or about or about 60 to 65 µm for example 50 µm, 65 µm, 76 µm, or 88µm. The nonwoven webs of the disclosure can be characterized as highloft or low loft. In general, loft refers to the ratio of thickness tobasis weight. High loft nonwoven webs can be characterized by a highratio of thickness to basis weight. As used herein, “high loft” refersto a nonwoven web of the disclosure having a basis weight as definedherein and a thickness exceeding 200 µm. The thickness of the nonwovenweb can be determined by according to ASTM D5729-97, ASTM D5736, and ISO9073-2:1995 and can include, for example, subjecting the nonwoven web toa load of 2 N and measuring the thickness. High loft materials can beused according to known methods in the art, for example, thru-airbonding or cross-lapping, which uses a cross-lapper to fold theunbounded web over onto itself to build loft and basis weight. Withoutintending to be bound by theory, in contrast to water-soluble filmswherein the solubility of the film can be dependent on the thickness ofthe film; the solubility of a nonwoven web including water-solublefibers is not believed to be dependent on the thickness of the web. Inthis regard, it is believed that because the individual fibers provide ahigher surface area than a water soluble film, regardless of thethickness of the film, the parameter that limits approach of water tothe fibers and, thereby, dissolution of the fibers in a water-solublenonwoven web is the basis weight.

The water-solubility of the nonwoven webs of the disclosure is generallya function of the type of fiber(s) used to prepare the web as well asthe basis weight of the water-dispersible web. Without intending to bebound by theory, for a nonwoven web comprising a sole fiber typecomprising a sole fiber forming material, it is believed that thesolubility profile of a nonwoven web follows the same solubility profileof the fiber(s) used to prepare the nonwoven web, and the solubilityprofile of the fiber generally follows the same solubility profile ofthe fiber forming polymer(s) from which the fiber is prepared. Forexample, for nonwoven webs comprising PVOH fibers, the degree ofhydrolysis of the polymer can be chosen such that the water-solubilityof the nonwoven web is also influenced. In general, at a giventemperature, as the degree of hydrolysis of the polymer increases frompartially hydrolyzed (88% DH) to fully hydrolyzed (≥98% DH), watersolubility of the polymer generally decreases. Thus, in one option, thenonwoven web can be cold water-soluble. For a co-poly(vinyl acetatevinyl alcohol) polymer that does not include any other monomers (e.g.,not copolymerized with an anionic monomer) a cold water-soluble web,soluble in water at a temperature of less than 10° C., can includefibers of the PVOH copolymer with a degree of hydrolysis in a range ofabout 75% to about 90%, or in a range of about 80% to about 90%, or in arange of about 85% to about 90%. In another option the nonwoven web canbe hot water-soluble. For a co-poly(vinyl acetate vinyl alcohol) polymerthat does not include any other monomers (e.g., not copolymerized withan anionic monomer) a hot water-soluble web, soluble in water at atemperature of at least about 60° C., can include fibers of the PVOHcopolymer with a degree of hydrolysis of at least about 98%.

Modification of the PVOH copolymer increases the solubility of the PVOHcopolymer. Thus, it is expected that at a given temperature thesolubility of a water-dispersible nonwoven web prepared from a modifiedPVOH copolymer, would be higher than that of a nonwoven web preparedfrom a PVOH copolymer without modification having the same degree ofhydrolysis as the PVOH copolymer. Following these trends, awater-dispersible nonwoven web having specific solubilitycharacteristics can be designed.

Surprisingly, for a nonwoven web including a blend of fiber types, eachfiber type having a sole fiber forming material, the solubility of thenonwoven web does not follow the rule of mixtures as would be expectedfor a blend of fiber types. Rather, for a nonwoven web including blendof two fiber types, when the two fiber types were provided in a ratioother than 1:1, the solubility of the nonwoven tended toward thesolubility of the less soluble fiber (i.e., the fiber that requireshigher temperatures to completely dissolve, and dissolves more slowly attemperatures below the complete dissolution temperature). For nonwovenwebs including 1:1 blends of fibers, the solubility of the nonwoven webwas generally lower than the solubility of the nonwoven webs includingblends other than 1:1 blends (i.e., at a given temperature, the nonwovenwebs including the 1:1 blends took longer to rupture, disintegrate, anddissolve than the nonwoven webs including, e.g., 3:1 and 1:3 ratios offiber types). This trend was especially pronounced at temperatures lowerthan the complete dissolution temperature of the less soluble fiber.

Inclusion of a water-insoluble fiber in a nonwoven web can also be usedto design a nonwoven web having specific solubility and/or delayedrelease properties (e.g., when the nonwoven web is included in awater-dispersible pouch). Without intending to be bound by theory, it isbelieved that as the weight percent of water-insoluble fiber included ina nonwoven web is increased (based on the total weight of the nonwovenweb), the solubility of the nonwoven web generally decreases and thedelayed release properties of a pouch comprising a nonwoven webgenerally increase. Upon contact with water at a temperature at or abovethe solubility temperature of the water-soluble fiber, a nonwoven webcomprising a water-soluble fiber and water-insoluble fiber will begin tothin as the water-soluble fiber dissolves, thereby breaking down the webstructure and/or increasing the pore size of the pores of the nonwovenweb. In general, the larger the break-down of the web structure orincrease in the pore size, the faster the water can access the contentsof the pouch and the faster the contents of the pouch will be released.Similarly, delayed release of the contents of a pouch comprising thenonwoven web of the disclosure can be achieved by using a blend ofwater-soluble fibers having different solubility properties and/ordifferent solubility temperatures. In general, for nonwoven websincluding water-soluble fibers comprising a polyvinyl alcohol fiberforming materials, at water temperatures of 50% or more of the completedissolution temperature of the water-soluble fibers (e.g., at 40° C. fora fiber having a complete dissolution temperature of 70° C.), the fiberswill undergo polymer network swelling and softening, but the overallstructure will remain intact. In embodiments wherein the nonwoven webincludes a water-soluble fiber and a water-insoluble fiber, the ratio ofsoluble fiber to insoluble fiber is not particularly limited. Thewater-soluble fiber can comprise about 1% to about 99%, about 20% toabout 80%, about 40% to about 90%, about 50% to about 90%, or about 60%to about 90% by weight of the total weight of the fibers and thewater-insoluble fiber can comprise about 1% to about 99%, about 20% toabout 80%, about 10% to about 60%, about 10% to about 50%, or about 10%to about 40% by weight of the total weight of the fibers.

Further, as the basis weight of the nonwoven web increases the rate ofdissolution of the web decreases, provided the fiber composition andbonding parameters remain constant, as there is more material to bedissolved. For example, at a given temperature, a water-soluble webprepared from fibers comprising PVOH polymer(s) and having a basisweight of, e.g., 40 g/m², is expected to dissolve slower than anotherwise-identical nonwoven web having a basis weight of, e.g., 30g/m². This relationship was especially prominent when the temperature ofthe water for dissolution was lower than the complete dissolutiontemperature of the fibers that made up the nonwoven web. Accordingly,basis weight can also be used to modify the solubility characteristicsof the water-dispersible nonwoven web. The nonwoven web can have anybasis weight in a range of about 1 g/m² to about 700 g/m², about 1 g/m²to about 600 g/m², about 1 g/m² to about 500 g/m², about 1 g/m² to about400 g/m², about 1 g/m² to about 300 g/m², about 1 g/m² to about 200g/m², about 1 g/m² to about 100 g/m², about 30 g/m² to about 100 g/m²,about 20 g/m² to about 100 g/m², about 20 g/m² to about 80 g/m², about25 g/m² to about 70 g/m², or about 30 g/m² to about 70 g/m².

Additionally, calendar settings have a secondary impact on thesolubility profile of a nonwoven web of the disclosure. For example, fornonwoven webs having identical fiber chemistry and similar basisweights, at a given calendar pressure, the solubility time of a nonwovenweb generally increases with increasing calendar temperature. Thisrelationship was especially prominent when the temperature of the waterfor dissolution was lower than the complete dissolution temperature ofthe fibers that made up the nonwoven web.

Without intending to be bound by theory, it is believed that solubility(in terms of time to dissolution, for example according to MSTM-205) ofa water-soluble nonwoven web is expected to surpass that of awater-soluble film of the same size (L x W) and/or mass, prepared fromthe same PVOH polymer. This is due to the higher surface area found inthe nonwoven compared to a film, leading to faster solubilization.

The nonwoven web of the disclosure can include any of the auxiliaryagents disclosed herein. Auxiliary agents can be dispersed throughoutthe web, e.g., between fibers, or applied to one of more surfaces of thenonwoven web. Auxiliary agents can be added to the nonwoven web duringthe melt-spun process, using a “co-form” process developed by KimberlyClark, as is well known in the art. Auxiliary agents can also be addedto one or more faces of a nonwoven web or article prepared therefrom, byany suitable means.

In embodiments, the nonwoven webs of the disclosure are substantiallyfree of auxiliary agents. As used herein and unless specified otherwise,“substantially free of auxiliary agents” means that the nonwoven webincludes less than about 0.01 wt.%, less than about 0.005 wt.%, or lessthan about 0.001 wt.% of auxiliary agents, based on the total weight ofthe nonwoven web.

In a one embodiment, one or more stationary powder spray guns are usedto direct an auxiliary agent powder stream towards the web or article,from one or more than one direction, while the web or article istransported through the coating zone by means of a belt conveyor. In analternative embodiment, an article is conveyed through a suspension ofan auxiliary agent powder in air. In yet another alternative embodimentthe articles are tumble-mixed with the auxiliary agent powder in atrough-like apparatus. In another embodiment, which can be combined withany other embodiment, electrostatic forces are employed to enhance theattraction between the auxiliary agent powder and the article. This typeof process is typically based on negatively charging the powderparticles and directing these charged particles to the groundedarticles. In other alternative embodiments, the auxiliary agent powderis applied to the article by a secondary transferring tool including,but not limited to rotating brushes which are in contact with the powderor by powdered gloves which can transfer the powder from a container tothe article. In yet another embodiment the auxiliary agent powder isapplied by dissolving or suspending the powder in a non-aqueous solventor carrier which is then atomized and sprayed onto the nonwoven orarticle. In one type of embodiment, the solvent or carrier subsequentlyevaporates, leaving the auxiliary agent powder behind. In one class ofembodiments, the auxiliary agent powder is applied to the nonwoven orarticle in an accurate dose. This class of embodiments utilizesclosed-system dry lubricant application machinery, such as PekuTECH’spowder applicator PM 700 D. In this process the auxiliary agent powder,optionally batch-wise or continuously, is fed to a feed trough ofapplication machinery. The nonwoven webs or articles are transferredfrom the output belt of a standard rotary drum pouch machine onto aconveyor belt of the powder application machine, wherein a controlleddosage of the auxiliary agent is applied to the nonwoven web or article.

Liquid auxiliary agents can be applied to a nonwoven web or article, forexample, by spin casting, spraying a solution such as an aerosolizedsolution, roll coating, flow coating, curtain coating, extrusion, knifecoating, and combinations thereof.

In embodiments, the nonwoven web can be colored, pigmented, and/or dyedto provide an improved aesthetic effect relative to water-soluble films.Suitable colorants can include an indicator dye, such as a pH indicator(e.g., thymol blue, bromothymol, thymolphthalein, and thymolphthalein),a moisture/water indicator (e.g., hydrochromic inks or leuco dyes), or athermochromic ink, wherein the ink changes color when temperatureincreases and/or decreases. Suitable colorants include, but are notlimited to a triphenylmethane dye, an azo dye, an anthraquinone dye, aperylene dye, an indigoid dye, a food, drug and cosmetic (FD&C)colorant, an organic pigment, an inorganic pigment, or a combinationthereof. Examples of colorants include, but are not limited to, FD&C Red#40; Red #3; FD&C Black #3; Black #2; Mica-based pearlescent pigment;FD&C Yellow #6; Green #3; Blue #1; Blue #2; titanium dioxide (foodgrade); brilliant black; and a combination thereof.

When included in a water-soluble fiber, the colorant can be provided inan amount of 0.01% to 25% by weight of the water-soluble polymermixture, such as, 0.02%, 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%,8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%,23%, and 24% by weight of the water-soluble polymer mixture.

Advantageously, the nonwoven webs of the disclosure can demonstratepreferential shrinking in the presence of heat and/or water (e.g.,humidity). Accordingly, the nonwoven webs can be heat and/or watershrunk when formed into packets. Further advantageously, the nonwovenwebs of the disclosure can demonstrate increased robustness (i.e.,mechanical properties) and improved solubility performance after storagein high heat and moisture environments (e.g., 38° C. and 80% relativehumidity (RH)). Such increased robustness and improved solubilityperformance is surprising as the expectation based on compositionallysimilar water-soluble films is that the robustness and solubilityperformance would be unaffected by storage in high heat and moistureconditions. In particular, after removal of comparable water-solublefilms from a conditioning environment, the water-soluble films willre-equilibrate with the surrounding environment leading to no long termor permanent changes in the performance properties of the films.

The nonwoven web of the disclosure can be used as a single layer or canbe layered with other nonwoven webs and/or water-soluble films. In someembodiments, the nonwoven web includes a single layer of nonwoven web.In some embodiments, the nonwoven web is a multilayer nonwoven webcomprising two or more layers of nonwoven webs. The one or more layerscan be laminated to each other. In refinements of the foregoingembodiment, the two or more layers can be the same (e.g., be preparedfrom the same fibers and having the same basis weight). In refinementsof the foregoing embodiment, the two or more layers can be different(e.g., be prepared from different types of fibers and/or have differentbasis weights). In embodiments, the nonwoven web can be laminated to awater-soluble film. In refinements of the foregoing embodiments, thenonwoven web and water-soluble film can be prepared from the samepolymer (e.g., a PVOH copolymer or a modified copolymer having aspecific viscosity, degree of hydrolysis, and amount of modification ifa modified polymer). In refinements of the foregoing embodiments, thenonwoven web and water-soluble film can be prepared from differentpolymers (e.g., the polymer used to prepare the fibers of the nonwovenweb can have different fiber chemistries (e.g., modifications),viscosities, degree of polymerization, degree of hydrolysis and/orsolubility than the polymer that makes up the water-soluble film).Advantageously, multilayered nonwoven webs and laminates can be used totune the moisture vapor transmission rate (MVTR) of a pouch or packetmade therefrom. Multilayer materials can be prepared according tovarious processes known in the art, for example, melt extrusion, coating(e.g., solvent coating, aqueous coating, or solids coating), sprayadhesion, material transfer, hot lamination, cold lamination, andcombinations thereof.

A multilayer nonwoven web can have a basis weight that is the sum of thebasis weights of the individual layers. Accordingly, a multilayernonwoven web will take longer to dissolve than any of the individuallayers provided as a single layer. In embodiments, the multilayernonwoven can have a basis weight in a range of about 1 g/m² to about 100g/m². Additionally, without intending to be bound by theory, it isbelieved that when pore sizes and pore arrangements are heterogeneousbetween layers, the pores in each layer will not align, therebyproviding a multilayer nonwoven web having smaller pores than theindividual layers. Accordingly, a nonporous water-dispersible nonwovenweb can be prepared by layering multiple porous water-dispersiblenonwoven webs.

The nonwoven web can also be laminated to a water-soluble film. Thelaminate can be formed using any known methods in the art including, butnot limited to heat and pressure, chemical bonding, and/or solventwelding. Chemical bonding can include ionically or covalentlyfunctionalizing a surface of the nonwoven web and/or a surface of thewater-soluble film such that when the surface of the nonwoven web comesin contact with the surface of the water-soluble film a chemicalreaction occurs and covalently bonds the nonwoven web and water-solublefilm together. The multilayer nonwoven web can include three or morelayers. In embodiments, the multilayer nonwoven web can include a firstlayer comprising a water-soluble film, a second layer comprising anonwoven web, and a third layer comprising a water-soluble film. Inembodiments, the multilayer nonwoven web can include a first layercomprising a nonwoven web, a second layer comprising a water-solublefilm, and a third layer comprising a nonwoven web.

Advantageously, the laminate can be prepared concurrently with pouchformation, e.g., using the heat applied during thermoforming to bond thenonwoven web and water-soluble film layers together. The water-solublefilm can have the same solubility and/or chemical compatibilitycharacteristics as the nonwoven web or the water-soluble film can havedifferent solubility and/or chemical compatibility characteristics fromthe nonwoven web. In embodiments, the water-soluble film has the samesolubility and/or chemical compatibility characteristics as the nonwovenweb. In some embodiments, the water-soluble film has differentsolubility and/or chemical compatibility characteristics from thenonwoven web. Advantageously, when the water-soluble film has differentsolubility and/or chemical compatibility characteristics from thenonwoven web the laminate can be used to form a pouch having an interiorsurface with a first solubility and/or chemical compatibility and anexterior surface having a second solubility and/or chemicalcompatibility.

The water-soluble film used for a laminate can be any water-solublefilm, e.g., one previously known in the art. The polymer used to formthe water-soluble film can be any water-soluble polymer, or combinationthereof, e.g., one described herein. The water-soluble film can containat least about 50 wt.%, 55 wt.%, 60 wt.%, 65 wt.%, 70 wt.%, 75 wt.%, 80wt.%, 85 wt.%, or 90 wt.% and/or up to about 60 wt.%, 70 wt.%, 80 wt.%,90 wt.%, 95 wt.%, or 99 wt.% of a water-soluble polymer, e.g., a PVOHpolymer or polymer blend.

The water-soluble film can contain other auxiliary agents and processingagents, such as, but not limited to, plasticizers, plasticizercompatibilizers, surfactants, lubricants, release agents, fillers,extenders, cross-linking agents, antiblocking agents, antioxidants,detackifying agents, antifoams, nanoparticles such as layeredsilicate-type nanoclays (e.g., sodium montmorillonite), bleaching agents(e.g., sodium metabisulfite, sodium bisulfite or others), aversiveagents such as bitterants (e.g., denatonium salts such as denatoniumbenzoate, denatonium saccharide, and denatonium chloride; sucroseoctaacetate; quinine; flavonoids such as quercetin and naringen; andquassinoids such as quassin and brucine) and pungents (e.g., capsaicin,piperine, allyl isothiocyanate, and resinferatoxin), and otherfunctional ingredients, in amounts suitable for their intended purposes.Embodiments including plasticizers are preferred. The amount of suchagents can be up to about 50 wt.%, 20 wt%, 15 wt%, 10 wt %, 5 wt.%, 4wt% and/or at least 0.01 wt.%, 0.1 wt%, 1 wt%, or 5 wt% of the film,individually or collectively.

The disclosure further provides a method of treating a nonwoven webcomprising a plurality of fibers comprising hydrolyzable polymers suchas a polymer comprising at least one of a vinyl acetate moiety or avinyl alcohol moiety and having a degree of hydrolysis less than 100%,the method comprising contacting at least a portion of the nonwoven webwith a hydrolysis agent solution as described herein to increase thedegree of hydrolysis of the hydrolyzable polymer of the fibers of theportion of the nonwoven web. In embodiments, the portion of the nonwovenweb contacted with the hydrolysis agent can be a face of the nonwovenweb. In embodiments, the contacting can be by immersion, spraying,transfer coating, wicking, foaming, brushing, rolling, humidification,vapor deposition, printing, or a combination thereof. In embodiments,the contacting occurs concurrently with bonding of the plurality of thefibers into the nonwoven web. In embodiments, the contacting and bondingcomprises chemical bonding. In embodiments, the contacting and bondingcomprises heat activated catalysis. The hydrolyzable polymer can be anyhydrolyzable polymer disclosed herein. In embodiments, the hydrolyzablepolymer comprises a polymer comprising at least one of a vinyl acetatemoiety or a vinyl alcohol moiety, which can be selected from a polyvinylacetate homopolymer, a polyvinyl alcohol homopolymer, a polyvinylalcohol copolymer, a modified polyvinyl alcohol copolymer, and acombination thereof. In embodiments, the polyvinyl alcohol copolymercomprises an anionically modified copolymer. In embodiments, theanionically modified copolymer comprises a carboxylate, a sulfonate, ora combination thereof. In embodiments, the fiber further comprises anadditional polymer. The hydrolysis agent solution can comprise anyhydrolysis agent disclosed herein and any solvent disclosed herein. Inembodiments, the hydrolysis agent comprises a metallic hydroxide, ametal hydride, a sulfite compound, a sulfur dioxide, a dithionate, athiosulfate, a hydrazine, oxalic acid, formic acid, ascorbic acid,dithiothreitol, a phosphite, a hypophosphite, phosphorous acid, sulfuricacid, sulphonic acid, hydrochloric acid, ammonium hydroxide, water, or acombination thereof. In embodiments, the hydrolysis agent is provided inan amount of about 0.2% to about 75% (w/w) based on the weight of thesolvent. In embodiments, the fiber is not soluble in the solvent priorto treatment, during treatment, and after treatment. In embodiments, thehydrolysis agent solution further comprises an activator.

The disclosure further provides a method of treating a nonwoven webcomprising a plurality of fibers comprising polymers such as a polymercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety and having a degree of hydrolysis of 100% or less and greaterthan 0%, the method comprising contacting at least a portion of thenonwoven web with an acylation agent solution to decrease the degree ofhydrolysis of the polymer of the fibers of the portion of the nonwovenweb. In embodiments, the portion of the nonwoven web contacted with theacylation agent can be a face of the nonwoven web. In embodiments, thecontacting can be by immersion, spraying, transfer coating, wicking,foaming, brushing, rolling, humidification, vapor deposition, printing,or a combination thereof. In embodiments, the contacting occursconcurrently with bonding of the plurality of the fibers into thenonwoven web. In embodiments, the contacting and bonding compriseschemical bonding. In embodiments, the contacting and bonding comprisesheat activated catalysis. The polymer can be any hydrolyzable polymerdisclosed herein that includes hydroxide or amine groups that can beacylated. In embodiments, the hydrolyzable polymer comprises a polyvinylalcohol polymer such as a polyvinyl alcohol copolymer, a modifiedpolyvinyl alcohol copolymer, and a combination thereof. In embodiments,the polyvinyl alcohol copolymer comprises an anionically modifiedcopolymer. In embodiments, the anionically modified copolymer comprisesa carboxylate, a sulfonate, or a combination thereof. In embodiments,the fiber further comprises an additional polymer. The acylation agentsolution can comprise any acylation agent disclosed herein and anysolvent disclosed herein. In embodiments, the fiber is not soluble inthe solvent prior to treatment, during treatment, and after treatment

The disclosure further provides a nonwoven web treated according to themethod of the disclosure. The disclosure provides a nonwoven webcomprising the fibers of the disclosure. The disclosure provides amultilayer nonwoven web comprising a first layer comprising a nonwovenweb treated according to the method of the disclosure or a nonwoven webcomprising the fibers of the disclosure.

Biodegradability

Polyvinyl alcohol polymers are generally biodegradable as they decomposein the presence of water and enzymes under aerobic, anaerobic, soil, andcompost conditions (in the presence of water). In general, as the degreeof hydrolysis of a polyvinyl alcohol polymer increases up to about 80%,the biodegradation activity of the polyvinyl alcohol polymer increases.Without intending to be bound by theory, it is believed that increasingthe degree of hydrolysis above 80% does not appreciably affectbiodegradability. Additionally, the stereoregularity of the hydroxylgroups of polyvinyl alcohol polymers has a large effect on thebiodegradability activity level and the more isotactic the hydroxylgroups of the polymer sequence, the higher degradation activity becomes.Without intending to be bound by theory, for soil and/or compostbiodegradation it is believed that a nonwoven web prepared from apolyvinyl alcohol fiber will have higher biodegradation activity levelsrelative to a water-soluble film prepared from a similar polyvinylalcohol polymer, due to the increase in the polymer surface areaprovided by the nonwoven web, relative to a film. Further, withoutintending to be bound by theory, it is believed that while the degree ofpolymerization of the polyvinyl alcohol polymer has little to no effecton the biodegradability of a film or nonwoven web prepared with thepolymer, the polymerization temperature may have an effect on thebiodegradability of a film or nonwoven because the polymerizationtemperature can affect the crystallinity and aggregating status of apolymer. In particular, as the crystallinity decreases, the polymerchain hydroxyl groups become less aligned in the polymer structure andthe polymer chains become more disordered allowing for chains toaccumulate as amorphous aggregates, thereby decreasing availability ofordered polymer structures such that the biodegradation activity isexpected to decrease for soil and/or compost biodegradation mechanismswherein the polymer is not dissolved. Without intending to be bound bytheory, it is believed that because the stereoregularity of the hydroxylgroups of polyvinyl alcohol polymers has a large effect onbiodegradability activity levels, the substitution of functionalitiesother than hydroxyl groups (e.g., anionic AMPS functional groups,carboxylate groups, or lactone groups) is expected to decrease thebiodegradability activity level, relative to a polyvinyl alcoholhomopolymer or copolymer having the same degree of hydrolysis, unlessthe functional group itself is also biodegradable, in which casebiodegradability of the polymer can be increased with substitution.Further, it is believed that while the biodegradability activity levelof a substituted polyvinyl alcohol (or a modified polyvinyl alcoholcopolymer) can be less than that of the corresponding homopolymer orcopolymer, the substituted polyvinyl alcohol will still exhibitbiodegradability.

Methods of determining biodegradation activity are known in the art, forexample, as described in Chiellini et al., Progress in Polymer Science,Volume 28, Issue 6, 2003, pp. 963-1014, which is incorporated herein byreference in its entirety. Further methods and standards can be found inECHA’s Annex XV Restriction Report - Microplastics, Version number 1,Jan. 11, 2019, which is incorporated herein by reference in itsentirety. Suitable standards include OECD 301B (ready biodegradability),OECD 301B (enhanced biodegradation), OECD 302B (inherentbiodegradability), OECD 311 (anaerobic), ASTM D5988 (soil).

In embodiments, the fibers and nonwoven webs of the disclosure can be ofthe standard ready biodegradation, enhanced biodegradation, or inherentbiodegradation. As used herein, the term “ready biodegradation” refersto a standard that is met if the material (e.g., a fiber) reached 60%biodegradation (mineralization) within 28 days of the beginning of thetest, according to the OECD 301B test as described in said ECHA’s AnnexXV. As used herein, the term “enhanced biodegradation” refers to astandard that is met if the material (e.g., a fiber) reaches 60%biodegradation within 60 days from the beginning of the test, accordingto the OECD 301B test as described in said ECHA’s Annex XV. Inembodiments, the fibers and nonwoven webs of the disclosure meet thestandards of ready biodegradation. In embodiments, the fibers andnonwoven webs of the disclosure meet the standards of readybiodegradation or enhanced degradation. In embodiments, the fibers andnonwoven webs of the disclosure meet the standards of inherentbiodegradation. In embodiments, the fibers and nonwoven webs of thedisclosure meet the standards of enhanced degradation. In embodiments,the fibers and nonwoven webs of the disclosure meet the standards ofinherent biodegradation, enhanced biodegradation, or readybiodegradation. In embodiments, the laminate (nonwoven and film) of thedisclosure meet the standards of ready biodegradation or enhancedbiodegradation.

Uses

The nonwoven webs of the disclosure are suitable for a variety ofcommercial applications. Suitable commercial applications for thenonwoven webs of the disclosure can include, but are not limited to,water-dispersible or flushable pouches and packets; medical uses such assurgical masks, medical packaging, shoe covers, wound dressing, and drugdelivery; filtration systems such as for gasoline and oil, mineralprocessing, vacuum bags, air filters, and allergen membranes orlaminates; personal care products such as for baby wipes, makeupremoving wipes, exfoliating clothes, makeup applicators, and wearableabsorbent articles such as diapers and adult incontinence products;office products such as shopping bags or envelopes; and others such aslens cleaning wipes, cleanroom wipes, potting material for plants,antibacterial wipes, agricultural seed strips, fabric softener sheets,garment/laundry bags, food wrapping, floor care wipes, pet care wipes,polishing tools, dust removal, and hand cleaning.

Sealed Pouches

The disclosure further provides a pouch comprising a nonwoven webaccording to the disclosure in the form of a pouch defining an interiorpouch volume. In some embodiments, the pouch can include a laminatecomprising a water-soluble film and a nonwoven web of the disclosure.The pouch can be a water-dispersible pouch, optionally a water-solublepouch and/or a flushable pouch. The disclosure further provides a methodof preparing a packet comprising a nonwoven web of the disclosure, themethod comprising forming a nonwoven web into the form of a pouch,filling the pouch with a composition to be enclosed therein, and sealingthe pouch to form a packet. In some embodiments, sealing includes heatsealing, solvent welding, adhesive sealing, or a combination thereof.

The nonwoven webs and laminates disclosed herein are useful for creatinga sealed article in the form of a pouch defining an interior pouchvolume to contain a composition therein for release into an aqueousenvironment. A “sealed article” optionally encompasses sealedcompartments having a vent hole, for example, in embodiments wherein thecompartment encloses a solid that off-gasses, but more commonly will bea completely sealed compartment.

The pouches may comprise a single compartment or multiple compartments.A pouch can be formed from two layers of nonwoven web or laminate sealedat an interface, or by a single nonwoven web or laminate that is foldedupon itself and sealed. The nonwoven web or laminate forms at least oneside wall of the pouch, optionally the entire pouch, and preferably anouter surface of the at least one sidewall. In another type ofembodiment, the nonwoven web or laminate forms an inner wall of thepacket, e.g., as a dividing wall between compartments. The nonwoven webor laminate can also be used in combination with a water-soluble film,e.g., as an exterior wall, inner wall, and/or compartment lid.

The composition enclosed in the pouch is not particularly limited, forexample including any of the variety of compositions described herein.In embodiments comprising multiple compartments, each compartment maycontain identical and/or different compositions. In turn, thecompositions may take any suitable form including, but not limited toliquid, solid, gel, paste, mull, pressed solids (tablets) andcombinations thereof (e.g., a solid suspended in a liquid).

In some embodiments, the pouches comprise multiple compartments. Themultiple compartments are generally superposed such that thecompartments share a partitioning wall interior to the pouch. Thecompartments of multi-compartment pouches may be of the same ordifferent size(s) and/or volume(s). The compartments of the presentmulti-compartment pouches can be separate or conjoined in any suitablemanner. In embodiments, the second and/or third and/or subsequentcompartments are superimposed on the first compartment. In oneembodiment, the third compartment may be superimposed on the secondcompartment, which is in turn superimposed on the first compartment in asandwich configuration. Alternatively, the second and third compartmentsmay be superimposed on the first compartment. However, it is alsoequally envisaged that the first, the second and/or third and/orsubsequent compartments are orientated side-by-side or in concentricorientations. The compartments may be packed in a string, eachcompartment being individually separable by a perforation line. Henceeach compartment may be individually torn-off from the remainder of thestring by the end-user. In some embodiments, the first compartment maybe surrounded by at least the second compartment, for example in atire-and-rim configuration, or in a pouch-in-a-pouch configuration.

The geometry of the compartments may be the same or different. Inembodiments the optionally third and subsequent compartments each have adifferent geometry and shape as compared to the first and secondcompartment. In these embodiments, the optionally third and subsequentcompartments are arranged in a design on the first or secondcompartment. The design may be decorative, educative, or illustrative,for example to illustrate a concept or instruction, and/or used toindicate origin of the product.

Methods of Making Pouches

Pouches and packets may be made using any suitable equipment and method.For example, single compartment pouches may be made using vertical formfilling, horizontal form filling, or rotary drum filling techniquescommonly known in the art. Such processes may be either continuous orintermittent. The nonwoven web, layered nonwoven web and film, orlaminate structure may be dampened, and/or heated to increase themalleability thereof. The method may also involve the use of a vacuum todraw the nonwoven web, layered nonwoven web and film, or laminatestructure into a suitable mold. The vacuum drawing the nonwoven web orlaminate into the mold can be applied for about 0.2 to about 5 seconds,or about 0.3 to about 3, or about 0.5 to about 1.5 seconds, once thenonwoven web, layered nonwoven web and film, or laminate structure is onthe horizontal portion of the surface. This vacuum can be such that itprovides an under-pressure in a range of 10 mbar to 1000 mbar, or in arange of 100 mbar to 600 mbar, for example.

The molds, in which packets may be made, can have any shape, length,width and depth, depending on the required dimensions of the pouches.The molds may also vary in size and shape from one to another, ifdesirable. For example, the volume of the final pouches may be about 5ml to about 300 ml, or about 10 ml to 150 ml, or about 20 ml to about100 ml, and that the mold sizes are adjusted accordingly.

Thermoforming

A thermoformable nonwoven web or laminate is one that can be shapedthrough the application of heat and a force. Thermoforming a nonwovenweb, layered nonwoven web and film, or laminate structure is the processof heating the nonwoven web, layered nonwoven web and film, or laminatestructure, shaping it (e.g., in a mold), and then allowing the resultingnonwoven web or laminate to cool, whereupon the nonwoven web or laminatewill hold its shape, e.g., the shape of the mold. The heat may beapplied using any suitable means. For example, the nonwoven web orlaminate may be heated directly by passing it under a heating element orthrough hot air, prior to feeding it onto a surface or once on asurface. Alternatively, it may be heated indirectly, for example byheating the surface or applying a hot item onto the nonwoven web orlaminate. In embodiments, the nonwoven web or laminate is heated usingan infrared light. The nonwoven web or laminate may be heated to atemperature in a range of about 50° C. to about 200° C., about 50° C. toabout 170° C., about 50° C. to about 150° C., about 50° C. to about 120°C., about 60° C. to about 130° C., about 70° C. to about 120° C., orabout 60° C. to about 90° C. Thermoforming can be performed by any oneor more of the following processes: the manual draping of a thermallysoftened nonwoven web or laminate over a mold, or the pressure inducedshaping of a softened nonwoven web or laminate to a mold (e.g., vacuumforming), or the automatic high-speed indexing of a freshly extrudedsheet having an accurately known temperature into a forming and trimmingstation, or the automatic placement, plug and/or pneumatic stretchingand pressuring forming of a nonwoven web or laminate.

Alternatively, the nonwoven web or laminate can be wetted by anysuitable means, for example directly by spraying a wetting agent(including water, a polymer composition, a plasticizer for the nonwovenweb or laminate composition, or any combination of the foregoing) ontothe nonwoven web or laminate, prior to feeding it onto the surface oronce on the surface, or indirectly by wetting the surface or by applyinga wet item onto the nonwoven web or laminate.

Once a nonwoven web or laminate has been heated and/or wetted, it may bedrawn into an appropriate mold, preferably using a vacuum. The fillingof the molded nonwoven web or laminate can be accomplished by utilizingany suitable means. In embodiments, the most preferred method willdepend on the product form and required speed of filling. Inembodiments, the molded nonwoven web or laminate is filled by in-linefilling techniques. The filled, open packets are then closed forming thepouches, using a second nonwoven web or laminate, by any suitablemethod. This may be accomplished while in horizontal position and incontinuous, constant motion. The closing may be accomplished bycontinuously feeding a second nonwoven web or laminate, preferablywater-soluble nonwoven web or laminate, over and onto the open packetsand then preferably sealing the first and second nonwoven web orlaminate together, typically in the area between the molds and thusbetween the packets.

Sealing the Pouches

Any suitable method of sealing the pouch and/or the individualcompartments thereof may be utilized. Non-limiting examples of suchmeans include heat sealing, solvent welding, solvent or wet sealing, andcombinations thereof. Typically, only the area which is to form the sealis treated with heat or solvent. The heat or solvent can be applied byany method, typically on the closing material, and typically only on theareas which are to form the seal. If solvent or wet sealing or weldingis used, it may be preferred that heat is also applied. Preferred wet orsolvent sealing/welding methods include selectively applying solventonto the area between the molds, or on the closing material, by forexample, spraying or printing this onto these areas, and then applyingpressure onto these areas, to form the seal. Sealing rolls and belts(optionally also providing heat) can be used, for example.

In embodiments, an inner nonwoven web or laminate is sealed to outernonwoven web(s) or laminate(s) by solvent sealing. The sealing solutionis generally an aqueous solution. In embodiments, the sealing solutionincludes water. In embodiments, the sealing solution includes water andfurther includes one or more polyols, diols and/or glycols such as1,2-ethanediol (ethylene glycol), 1,3-propanediol, 1,2-propanediol,1,4-butanediol (tetramethylene glycol), 1,5-pantanediol (pentamethyleneglycol), 1,6-hexanediol (hexamethylene glycol), 2,3-butanediol,1,3-butanediol, 2-methyl-1,3-propanediol, various polyethylene glycols(e.g., diethylene glycol, triethylene glycol), and combinations thereof.In embodiments, the sealing solution includes erythritol, threitol,arabitol, xylitol, ribitol, mannitol, sorbitol, galactitol, fucitol,iditol, inositol, volemitol, isomal, maltitol, lactitol. In embodiments,the sealing solution includes a water-soluble polymer.

The sealing solution can be applied to the interfacial areas of theinner nonwoven web or laminate in any amount suitable to adhere theinner and outer nonwoven webs or laminates. As used herein, the term“coat weight” refers to the amount of sealing solution applied to thenonwoven web or laminate in grams of solution per square meter ofnonwoven web or laminate. In general, when the coat weight of thesealing solvent is too low, the nonwoven webs or laminates do notadequately adhere and the risk of pouch failure at the seams increases.Further, when the coat weight of the sealing solvent is too high, therisk of the solvent migrating from the interfacial areas increases,increasing the likelihood that etch holes may form in the sides of thepouches. The coat weight window refers to the range of coat weights thatcan be applied to a given film while maintaining both good adhesion andavoiding the formation of etch holes. A broad coat weight window isdesirable as a broader window provides robust sealing under a broadrange of operations. Suitable coat weight windows are at least about 3g/m², or at least about 4 g/m², or at least about 5 g/m², or at leastabout 6 g/m².

Cutting the Packets

Formed packets may be cut by a cutting device. Cutting can beaccomplished using any known method. It may be preferred that thecutting is also done in continuous manner, and preferably with constantspeed and preferably while in horizontal position. The cutting devicecan, for example, be a sharp item, or a hot item, or a laser, whereby inthe latter cases, the hot item or laser ‘burns’ through the film/sealing area.

Forming and Filling Multi-Compartment Pouches

The different compartments of a multi-compartment pouches may be madetogether in a side-by-side style or concentric style wherein theresulting, cojoined pouches may or may not be separated by cutting.Alternatively, the compartments can be made separately.

In embodiments, pouches may be made according to a process comprisingthe steps of: a) forming a first compartment (as described above); b)forming a recess within or all of the closed compartment formed in step(a), to generate a second molded compartment superposed above the firstcompartment; c) filling and closing the second compartments by means ofa third nonwoven web, laminate, or film; d) sealing the first, secondand third nonwoven web, laminate, or film; and e) cutting the nonwovenwebs or laminates to produce a multi-compartment pouch. The recessformed in step (b) may be achieved by applying a vacuum to thecompartment prepared in step (a).

In embodiments, second, and/or third compartment(s) can be made in aseparate step and then combined with the first compartment as describedin European Patent Application Number 08101442.5 or U.S. Pat.Application Publication No. 2013/240388 A1 or WO 2009/152031.

In embodiments, pouches may be made according to a process comprisingthe steps of: a) forming a first compartment, optionally using heatand/or vacuum, using a first nonwoven web or laminate on a first formingmachine; b) filling the first compartment with a first composition; c)optionally filling the second compartment with a second composition; d)sealing the first and optional second compartment with a second nonwovenweb or laminate to the first nonwoven web or laminate; and e) cuttingthe nonwoven webs or laminates to produce a multi-compartment pouch.

In embodiments, pouches may be made according to a process comprisingthe steps of: a) forming a first compartment, optionally using heatand/or vacuum, using a first nonwoven web or laminate on a first formingmachine; b) filling the first compartment with a first composition; c)on a second forming machine, deforming a second nonwoven web orlaminate, optionally using heat and vacuum, to make a second andoptionally third molded compartment; d) filling the second andoptionally third compartments; e) sealing the second and optionallythird compartment using a third nonwoven web or laminate; f) placing thesealed second and optionally third compartments onto the firstcompartment; g) sealing the first, second and optionally thirdcompartments; and h) cutting the nonwoven web or laminate to produce amulti-compartment pouch.

The first and second forming machines may be selected based on theirsuitability to perform the above process. In embodiments, the firstforming machine is preferably a horizontal forming machine, and thesecond forming machine is preferably a rotary drum forming machine,preferably located above the first forming machine.

It should be understood that by the use of appropriate feed stations, itmay be possible to manufacture multi-compartment pouches incorporating anumber of different or distinctive compositions and/or different ordistinctive liquid, gel or paste compositions.

In embodiments, the nonwoven web or laminate and/or pouch is sprayed ordusted with a suitable material, such as an active agent, a lubricant,an aversive agent, or mixtures thereof. In embodiments, the nonwoven webor laminate and/or pouch is printed upon, for example, with an inkand/or an active agent.

Vertical Form, Fill and Seal

In embodiments, the nonwoven web or laminate of the disclosure can beformed into a sealed article. In embodiments, the sealed article is avertical form, filled, and sealed article. The vertical form, fill, andseal (VFFS) process is a conventional automated process. VFFS includesan apparatus such as an assembly machine that wraps a single piece ofthe nonwoven web or laminate around a vertically oriented feed tube. Themachine heat seals or otherwise secures the opposing edges of thenonwoven web or laminate together to create the side seal and form ahollow tube of nonwoven web or laminate. Subsequently, the machine heatseals or otherwise creates the bottom seal, thereby defining a containerportion with an open top where the top seal will later be formed. Themachine introduces a specified amount of flowable product into thecontainer portion through the open top end. Once the container includesthe desired amount of product, the machine advances the nonwoven web orlaminate to another heat sealing device, for example, to create the topseal. Finally, the machine advances the nonwoven web or laminate to acutter that cuts the film immediately above the top seal to provide afilled package.

During operation, the assembly machine advances the nonwoven web orlaminate from a roll to form the package. Accordingly, the nonwoven webor laminate must be able to readily advance through the machine and notadhere to the machine assembly or be so brittle as to break duringprocessing.

Pouch Contents

In any embodiment, the pouch can contain (enclose) a composition in thedefined interior volume of the pouch. The composition can be selectedfrom a liquid, solid or combination thereof. In embodiments wherein thecomposition includes a liquid, the nonwoven web can be a nonporousnonwoven web or a porous nonwoven web laminated with a water-solublefilm, the water-soluble film forming the inner surface of the pouch. Inembodiments wherein the composition is a solid, the pouch can comprise anonporous nonwoven web, a porous nonwoven web laminated with awater-soluble film, or a porous nonwoven web. In embodiments wherein thepouch includes a porous nonwoven web, the particle size of the solidcomposition is smaller than the pore size of the nonwoven web.

In embodiments, the sealed articles of the disclosure can enclose in theinterior pouch volume a composition comprising a liquid laundrydetergent, an agricultural composition, an automatic dish washingcomposition, household cleaning composition, a water-treatmentcomposition, a personal care composition, a food and nutritivecomposition, an industrial cleaning composition, a medical composition,a disinfectant composition, a pet composition, an office composition, alivestock composition, an industrial composition, a marine composition,a mercantile composition, a military composition, a recreationalcomposition, or a combination thereof. In embodiments, thewater-dispersible sealed articles of the disclosure can enclose in theinterior pouch volume a composition comprising a liquid laundrydetergent, an agricultural composition, an automatic dish washingcomposition, a household cleaning composition, a water-treatmentcomposition, a personal care composition, a food and nutritivecomposition, an industrial cleaning composition, or a combinationthereof. In embodiments, the water-dispersible sealed articles of thedisclosure can enclose in the interior pouch volume a compositioncomprising a liquid laundry detergent, an agricultural composition, anautomatic dish washing composition, a household cleaning composition, awater-treatment composition, a personal care composition, or acombination thereof. In embodiments, the water-dispersible sealedarticles of the disclosure can enclose in the interior pouch volume acomposition comprising an agricultural composition or a water-treatmentcomposition.

As used herein, “liquid” includes free-flowing liquids, as well aspastes, gels, foams and mousses. Non-limiting examples of liquidsinclude light duty and heavy duty liquid detergent compositions, dishdetergent for hand washing and/or machine washing; hard surface cleaningcompositions, fabric enhancers, detergent gels commonly used forlaundry, bleach and laundry additives, shaving creams, skin care, haircare compositions (shampoos and conditioners), and body washes. Suchdetergent compositions may comprise a surfactant, a bleach, an enzyme, aperfume, a dye or colorant, a solvent and combinations thereof.Optionally, the detergent composition is selected from the groupconsisting of a laundry detergent, a dishwashing detergent, a hardsurface cleaning composition, fabric enhancer compositions, shavingcreams, skin care, hair care compositions (shampoos and conditioners),and body washes, and combinations thereof.

Non-limiting examples of liquids include agricultural compositions,automotive compositions, aviation compositions, food and nutritivecompositions, industrial compositions, livestock compositions, marinecompositions, medical compositions, mercantile compositions, militaryand quasi-military compositions, office compositions, recreational andpark compositions, pet compositions, and water-treatment compositions,including cleaning and detergent compositions applicable to any suchuse.

Gases, e.g., suspended bubbles, or solids, e.g., particles, may beincluded within the liquids. A “solid” as used herein includes, but isnot limited to, powders, agglomerates, and mixtures thereof.Non-limiting examples of solids include: granules, micro-capsules,beads, noodles, and pearlised balls. Solid compositions may provide atechnical benefit including, but not limited to, through-the-washbenefits, pre-treatment benefits, and/or aesthetic effects.

The composition may be a non-household care composition. For example, anon-household care composition can be selected from agriculturalcompositions, aviation compositions, food and nutritive compositions,industrial compositions, livestock compositions, marine compositions,medical compositions, mercantile compositions, military andquasi-military compositions, office compositions, recreational and parkcompositions, pet compositions, and water-treatment compositions,including cleaning and detergent compositions applicable to any such usewhile excluding fabric and household care compositions

In one type of embodiment, the composition can include an agrochemical,e.g., one or more insecticides, fungicides, herbicides, pesticides,miticides, repellants, attractants, defoliaments, plant growthregulators, fertilizers, bactericides, micronutrients, and traceelements. Suitable agrochemicals and secondary agents are described inU.S. Pat. Nos. 6,204,223 and 4,681,228 and EP 0989803 A1. For example,suitable herbicides include paraquat salts (for example paraquatdichloride or paraquat bis(methylsulphate), diquat salts (for examplediquat dibromide or diquat alginate), and glyphosate or a salt or esterthereof (such as glyphosate isopropylammonium, glyphosate sesquisodiumor glyphosate trimesium, also known as sulfosate). Incompatible pairs ofcrop protection chemicals can be used in separate chambers, for exampleas described in U.S. Pat. No. 5,558,228. Incompatible pairs of cropprotection chemicals that can be used include, for example, bensulfuronmethyl and molinate; 2,4-D and thifensulfuron methyl;2,4-D and methyl2-[[[[N-4-methoxy-6-methyl-1,3,5-triazine-2-yl)-N-methylamino]carbonyl]amino]-sulfonyl]benzoate;2,4-D and metsulfuron methyl; maneb or mancozeb and benomyl; glyphosateand metsulfuron methyl; tralomethrin and any organophosphate such asmonocrotophos or dimethoate; bromoxynil andN-[[4,6-dimethoxypyrimidine-2-yl)-amino]carbonyl]-3-(ethylsulfonyl)-2-pyridine -sulfonamide; bromoxyniland methyl2-[[[[(4-methyl-6-methoxy)-1,3,5-triazin-2-yl)amino]carbonyl]amino]sulfonyl]-benzoate;bromoxynil and methyl2-[[[[N-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)-N-methylamino]carbonyl]amino]-sulfonyl]benzoate.In another, related, type of embodiment, the composition can include oneor more seeds, optionally together with soil, and further optionallytogether with one or more additional components selected from mulch,sand, peat moss, water jelly crystals, and fertilizers, e.g., includingtypes of embodiments described in U.S. Pat. No. 8,333,033.

In another type of embodiment, the composition is a water-treatmentagent. Such agents can include harsh chemicals, such as aggressiveoxidizing chemicals, e.g., as described in U.S. Pat. ApplicationPublication No. 2014/0110301 and U.S. Pat. No. 8,728,593. For example,sanitizing agents can include hypochlorite salts such as sodiumhypochlorite, calcium hypochlorite, and lithium hypochlorite;chlorinated isocyanurates such as dichloroisocyanuric acid (alsoreferred to as “dichlor” or dichloro-s-triazinetrione, 1 ,3-dichloro- 1,3,5-triazinane-2,4,6-trione) and trichloroisocyanuric acid (alsoreferred to as “trichlor” or1,3,5-trichloro-1,3,5-triazinane-2,4,6-trione). Salts and hydrates ofthe sanitizing compounds are also contemplated. For example,dichloroisocyanuric acid may be provided as sodium dichloroisocyanurate,sodium dichloroisocyanurate acid dihydrate, among others. Brominecontaining sanitizing agents may also be suitable for use in unit dosepackaging applications, such as 1,3-dibromo-5,5-dimethylhydantoin(DBDMH), 2,2- dibromo-3-nitrilopropionamide (DBNPA), dibromocyano aceticacid amide, 1-bromo- 3-chloro-5,5-dimethylhydantoin; and2-bromo-2-nitro- 1,3 -propanediol, among others. The oxidizing agent canbe one described in U.S. Pat. No. 7,476,325, e.g., potassium hydrogenperoxymonosulfate. The composition can be a pH-adjusting chemical, e.g.,as described in U.S. Pat. Application Publication No. 2008/0185347, andcan include, for example, an acidic component and an alkaline componentsuch that the composition is effervescent when contacted with water, andadjusts the water pH. Suitable ingredients include sodium bicarbonate,sodium bisulfate, potassium hydroxide, sulfamic acid, organic carboxylicacids, sulfonic acids, and potassium dihydrogen phosphate. A bufferblend can include boric acid, sodium carbonate, glycolic acid, and oxonemonopersulfate, for example.

A water-treatment agent can be or can include a flocculant, e.g., asdescribed in U.S. Pat. Application Publication No. 2014/0124454. Theflocculant can include a polymer flocculant, e.g., polyacrylamide, apolyacrylamide copolymer such as an acrylamide copolymers ofdiallydimethylammonium chloride (DADMAC), dimethylaminoethylacrylate(DMAEA), dimethylaminoethylmethacrylate (DMAEM), 3-methylamidepropyltrimethylammonium chloride (MAPTAC) or acrylic acid; acationic polyacrylamide; an anionic polyacrylamide; a neutralpolyacrylamide; a polyamine; polyvinylamine; polyethylene imine;polydimethyldiallylammonium chloride; poly oxyethylene; polyvinylalcohol; polyvinyl pyrrolidone; polyacrylic acid; polyphosphoric acid;polystyrene sulfonic acid; or any combination thereof. A flocculant canbe selected from chitosan acetate, chitosan lactate, chitosan adipate,chitosan glutamate, chitosan succinate, chitosan malate, chitosancitrate, chitosan fumarate, chitosan hydrochloride, and combinationsthereof. The water-treating composition can include a phosphate removingsubstance, e.g., one or more selected from a zirconium compound, a rareearth lanthanide salt, an aluminum compound, an iron compound, or anycombination thereof.

The composition can be a limescale removing composition, e.g., citric ormaleic acid or a sulfate salt thereof, or any mixture thereof, e.g., asdescribed in U.S. Pat. Application No. 2006/0172910.

Various other types of compositions are contemplated for use in thepackets described herein, including particulates, for example downfeathers, e.g., as described in US RE29059 E; super absorbent polymers,e.g., as described in U.S. Pat. Application Publication Nos.2004/0144682 and 2006/0173430; pigments and tinters, e.g., as describedin U.S. Pat. No. 3,580,390 and U.S. Pat. Application Publication No.2011/0054111; brazing flux (e.g., alkali metal fluoroaluminates, alkalimetal fluorosilicates and alkali metal fluorozincates), e.g., asdescribed in U.S. Pat. No. 8,163,104; food items (e.g., coffee powder ordried soup) as described in U.S. Pat. Application Publication No.2007/0003719; and wound dressings, e.g., as described in U.S. Pat. No.4,466,431.

In pouches comprising laundry, laundry additive and/or fabric enhancercompositions, the compositions may comprise one or more of the followingnon-limiting list of ingredients: fabric care benefit agent; detersiveenzyme; deposition aid; rheology modifier; builder; bleach; bleachingagent; bleach precursor; bleach booster; bleach catalyst; perfume and/orperfume microcapsules (see for example U.S. 5,137,646); perfume loadedzeolite; starch encapsulated accord; polyglycerin esters; whiteningagent; pearlescent agent; enzyme stabilizing systems; scavenging agentsincluding fixing agents for anionic dyes, complexing agents for anionicsurfactants, and mixtures thereof; optical brighteners or fluorescers;polymer including but not limited to soil release polymer and/or soilsuspension polymer; dispersants; antifoam agents; non-aqueous solvent;fatty acid; suds suppressors, e.g., silicone suds suppressors (see: U.S.Publication No. 2003/0060390 A1, ¶ 65-77); cationic starches (see: U.S.2004/0204337 A1 and U.S. 2007/0219111 A1); scum dispersants (see: U.S.2003/0126282 A1, ¶89-90); substantive dyes; hueing dyes (see: U.S.2014/0162929 A1); colorants; opacifier; antioxidant; hydrotropes such astoluenesulfonates, cumenesulfonates and naphthalenesulfonates; colorspeckles; colored beads, spheres or extrudates; clay softening agents;anti-bacterial agents. Any one or more of these ingredients is furtherdescribed in described in U.S. Pat. Application Publication Number U.S.2010/305020 A1, U.S. Publication No. 2003/0139312A1 and U.S. Pat.Application Publication No. U.S. 2011/0023240 A1. Additionally, oralternatively, the compositions may comprise surfactants, quaternaryammonium compounds, and/or solvent systems. Quaternary ammoniumcompounds may be present in fabric enhancer compositions, such as fabricsofteners, and comprise quaternary ammonium cations that are positivelycharged polyatomic ions of the structure NR₄ ⁺, where R is an alkylgroup or an aryl group.

Composite Articles

Composite articles of the disclosure include at least two layers ofnonwoven webs. The composite articles of the disclosure can have a firstlayer of a first nonwoven web including a first plurality of fibershaving a first diameter, a second layer of a second nonwoven webcomprising a second plurality of fibers having a second diameter, and afirst interface comprising at least a portion of the first nonwoven weband at least a portion of the second nonwoven web, wherein the portionof the first nonwoven web and the portion of the second nonwoven web arefused, and wherein the second diameter is smaller than the firstdiameter. Any nonwoven layer of the composite article can include awater-soluble film laminated thereto.

Composite articles of the disclosure can provide one or more advantages,including but not limited to, increased mechanical strength relative toa nonwoven web identical to a single layer of the composite articlealone, enhanced liquid acquisition function relative to a nonwoven webidentical to a single layer of the composite article alone (e.g., for aliquid acquisition layer of a diaper, or for a spill absorbing wipe),and/or enhanced retention of fluids and/or active compositions relativeto a nonwoven web identical to a single layer of the composite articlealone (e.g., an active lotion for a wet wipe).

The first interface including at least a portion of the first nonwovenweb and at least a portion of the second nonwoven web is the area of thecomposite where the first and second nonwoven webs overlap and the firstplurality of fibers and the second plurality of fibers are intermingled.In general, the portion of the first nonwoven web that forms the firstinterface is an exterior surface of the first nonwoven web. Inembodiments, the first interface comprises 50% or less of the thicknessof the first nonwoven web, 40% or less, 30% or less, 25% or less, 20% orless, 10% or less, 5% or less, 2.5% or less, or 1% or less of thethickness of the first nonwoven web. In embodiments, the first interfacecomprises at least 0.1%, at least 0.5%, at least 1%, or at least 5% ofthe thickness of the first nonwoven. In embodiments, the first interfacecomprises about 0.1% to about 25% of the thicknesses of the firstnonwoven. In general, the portion of the second nonwoven web that formsthe interface is an exterior surface of the second nonwoven web. Inembodiments, the interface comprises 75% or less, 70% or less, 60% orless, 50% or less, 40% or less, 30% or less, 25% or less, 20% or less,or 15% or less of the thickness of the second nonwoven web. Inembodiments, the first interface comprises at least 1%, at least 5%, atleast 10%, at least 20%, at least 25%, at least 30%, or at least 40% ofthe thickness of the second nonwoven web. In embodiments, the firstinterface comprises from about 1% to about 75% of the thickness of thesecond nonwoven web.

As used herein, and unless specified otherwise, two layers of nonwovenwebs are “fused” if at least a portion of the fibers from each web arebonded to fibers from the other web. As described herein, bonding of thefibers includes entangling of the fibers. The two layers of nonwovenwebs can be fused using any suitable method. In embodiments, the portionof the first nonwoven web and the portion of the second nonwoven web arethermally fused, solvent fused, or both. In embodiments, the portion ofthe first nonwoven web and the portion of the second nonwoven web arethermally fused. Thermal fusion can include the use of heat and/orpressure. In embodiments, one or both of two discrete nonwoven webs canbe heated until the fibers are soft and the webs can then be pressedtogether such that when the fibers cool at least a portion of fibersfrom each web are bonded to at least a portion of fibers from the otherweb. In embodiments, one or both of the first and second nonwoven webscan be melt-spun and applied in an inline process such that heated, softfibers are applied directly to a pre-formed nonwoven web after passingthrough the die assembly and fuse to the fibers of the pre-formednonwoven forming a fused interface. In embodiments, the portion of thefirst nonwoven web and the portion of the second nonwoven web aresolvent fused. Solvent fusion can include the application of a bindersolution to one or both of the nonwoven webs followed by contacting thenonwoven webs such that upon drying, at least a portion of fibers fromeach web are bonded to at least a portion of fibers from the other web.Solvent fusion can occur as a discrete process including two discretepre-formed webs or can be an inline process wherein a binder solution isapplied to a pre-formed nonwoven web and a second nonwoven web is formedon the pre-formed nonwoven web in a continuous process. The bindersolution for solvent fusion of the nonwoven web can be any bindersolution described herein for binding. As used herein, and unlessspecified otherwise, a “pre-formed nonwoven web” encompasses nonwovenwebs formed but not bonded and nonwoven webs that have been formed andbonded. As used herein, and unless specified otherwise, a “discretenonwoven web” encompasses nonwoven webs formed by carding or airlayingstaple fibers, or by continuous processes, and the nonwoven webs may ormay not be bonded. In embodiments, the fusing of two nonwoven webs canalso be used to bond one or both of the nonwoven webs.

In embodiments, the first interface is solvent fused and the solvent isselected from the group consisting of water, ethanol, methanol, DMSO,glycerin, and a combination thereof. In embodiments, the first interfaceis solvent fused and the solvent is selected from the group consistingof water, glycerin, and a combination thereof. In embodiments, the firstinterface is solvent fused using a binder solution comprising polyvinylalcohol and water, glycerin, or a combination thereof. In embodiments,the first interface is solvent fused using a binder solution comprisingpolyvinyl alcohol, latex, or a combination thereof and water, glycerin,or a combination thereof.

As used herein, and unless specified otherwise, a first type of fiberhas a diameter that is “smaller than” the diameter of a second type offiber if the average fiber diameter for the first type of fiber is lessthan the average fiber diameter of the second type of fiber. Forexample, the first type of fiber can have an overlapping diameter sizedistribution with the second type of fiber and still have a smallerdiameter as long as the average fiber diameter for the first type offiber is smaller than the average fiber diameter of the second type offiber. In embodiments, the smaller fiber type has an average fiberdiameter that is smaller than the smallest diameter of the diameter sizedistribution of the larger fiber type. A difference in diameter ispresent if the difference can be visualized using projection microscopeimaging as outlined in SO137:2015. In embodiments, the difference indiameter between the smaller fiber type and the larger fiber type can besubmicron, for example, if multiple melt-spun layers are used. Inembodiments, the difference in the diameter between the smaller fibertype and the larger fiber type can be about 1 micron to about 300micron, about 5 micron to about 300 micron, about 5 micron to about 250micron, about 5 micron to about 200 micron, about 10 micron to about 150micron, about 10 micron to about 100 micron, about 10 micron to about 90micron, about 15 micron to about 80 micron, about 15 micron to about 70micron, about 20 micron to about 60 micron, about 20 micron to about 50micron, or about 25 micron to about 45 micron. In embodiments, thedifference in diameter between the smaller fiber type and the largerfiber type can be about 5 micron to about 75 micron. In embodiments, thedifference in diameter between the smaller fiber type and the largerfiber type can be about 20 micron to about 80 micron. Without intendingto be bound by theory, it is believed that providing a composite of twononwoven webs wherein the nonwoven webs are fused and the secondnonwoven web has a fiber diameter that is smaller than the firstnonwoven web advantageously can improve the adsorption/absorption rateand fluid capacity of the composite article, directadsorption/absorption from larger diameter fibers to smaller diameterfibers to move the fluid preferentially; increase the surface to volumeratio of a nonwoven composite article as compared to single diametermaterials resulting in increased loading capacity, and/or improveddispersion and/or total dissolution of the nonwoven composite article ascompared to a nonwoven having a single diameter material. The averagediameters of the fibers in the individual web layers can be anydiameters provided herein. In embodiments, the first plurality of fibersin the first layer of first nonwoven can have a diameter of about 10micron to about 300 micron, about 50 micron to about 300 micron, orabout greater than about 100 micron to about 300 micron. In embodiments,the first plurality of fibers can have an average diameter of greaterthan about 100 micron to about 300 micron. In embodiments wherein anonwoven layer of the nonwoven composite material includes a blend offiber types having different diameters, if the distribution of fiberdiameters is monomodal, the average fiber diameter refers to the averagefiber diameter of the blend. The blend of fiber types can havedistribution of fiber diameters in the nonwoven layer that bimodal orhigher. When a blend of fibers has a bimodal or higher-modal diameterdistribution, a fiber has a smaller diameter than the fibers of saidblend when the fiber has an average fiber diameter less than the averagefor the distribution of the smallest diameter fibers of the blend, and afiber is larger than the fibers of said blend when the fiber has anaverage fiber diameter that is greater than the average for thedistribution of the larger diameter fibers of the blend.

In embodiments, the composite article further comprises a third layer ofa third nonwoven web comprising a third plurality of fibers. Inembodiments wherein the nonwoven composite article includes a thirdlayer of a third nonwoven web, the second layer can be provided betweenthe first layer and the third layer and at least a second portion of thesecond nonwoven web and at least a portion of the third nonwoven web canbe fused, providing a second interface. The second interface includingat least a second portion of the second nonwoven web and at least aportion of the third nonwoven web is the area of the composite where thesecond and third nonwoven webs overlap and the second plurality offibers and the third plurality of fibers are intermingled. In someembodiments, and depending on the thickness of the second layer ofsecond nonwoven web, the first plurality of fibers and the thirdplurality of fibers may become intermingled and/or fused such that thereis no clear delineation between the first interface and the secondinterface. In general, the portion of the second nonwoven web that formsthe second interface is an exterior surface of the second nonwoven webopposite from the exterior surface of the second nonwoven web fused tothe first nonwoven web. In embodiments, the second interface comprises75% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% orless, 25% or less, 20% or less, or 15% or less of the thickness of thesecond nonwoven web. In embodiments, the second interface comprises atleast 1%, at least 5%, at least 10%, at least 20%, at least 25%, atleast 30%, or at least 40% of the thickness of the second nonwoven web.In embodiments, the second interface comprises from about 1% to about75% of the thickness of the second nonwoven web. In embodiments, theportion of the third nonwoven web that forms the second interface is anexterior surface of the third nonwoven web. In embodiments, the secondinterface comprises 50% or less of the thickness of the third nonwovenweb, 40% or less, 30% or less, 25% or less, 20% or less, 10% or less, 5%or less, 2.5% or less, or 1% or less of the thickness of the firstnonwoven web. In embodiments, the second interface comprises at least0.1%, at least 0.5%, at least 1%, or at least 5% of the thickness of thethird nonwoven. In embodiments, the second interface comprises about0.1% to about 25% of the thicknesses of the third nonwoven.

In embodiments, the second portion of the second nonwoven web and theportion of the third nonwoven web are thermally fused, solvent fused, orboth. In embodiments, the second portion of the second nonwoven web andthe portion of the third nonwoven web are thermally fused. Inembodiments, the second portion of the second nonwoven web and theportion of the third nonwoven web are solvent fused.

In embodiments, the second interface is solvent fused and the solvent isselected from the group consisting of water, ethanol, methanol, DMSO,glycerin, and a combination thereof. In embodiments, the secondinterface is solvent fused and the solvent is selected from the groupconsisting of water, glycerin, and a combination thereof. Inembodiments, the second interface is solvent fused using a bindersolution comprising polyvinyl alcohol and water, glycerin, or acombination thereof. In embodiments, the second interface is solventfused using a binder solution comprising polyvinyl alcohol, latex, or acombination thereof and water, glycerin, or a combination thereof.

In embodiments, the first layer of first nonwoven web and the secondlayer of second nonwoven web have different porosities. As used herein,and unless specified otherwise, two nonwoven webs have “differentporosities” when the difference in porosities of the nonwoven web is atleast about 1%. In embodiments, the difference in porosities between twolayers of nonwoven webs in the composite articles can be about 1% toabout 20%. For example, one layer of nonwoven web in a composite articlecan have a porosity of about 80% and a second layer of nonwoven web inthe composite article can have a porosity of about 85%, a 5% differencein porosity. In embodiments, the porosity of the second nonwoven web isless than the porosity of the first nonwoven web. In embodiments, theporosity of the second nonwoven web is the same as the porosity of thefirst nonwoven web. As used herein, and unless specified otherwise, twononwoven webs have the “same porosity” if the difference in porosityvalues between the two nonwoven webs is less than 1%.

In embodiments wherein the composite article comprises a third layer ofa third nonwoven web, the third nonwoven web can have a porosity that isthe same or different from the first nonwoven web. In embodiments, thethird nonwoven web can have the same porosity as the first nonwoven web.In embodiments, the third nonwoven web can have a different porositythan the first nonwoven web. In embodiments, the third nonwoven web canbe less porous than the first nonwoven web. In embodiments, the thirdnonwoven web can have the same porosity as the second nonwoven web. Inembodiments, the third nonwoven web can have a different porosity thanthe second nonwoven web. In embodiments, the third nonwoven web can beless porous than the second nonwoven web. In embodiments, the secondnonwoven web can be less porous than the first nonwoven web and thethird nonwoven web can be less porous than the second nonwoven web. Inembodiments, the nonwoven composite article can have a gradient ofporosity between the layers of nonwoven web, wherein one exteriorsurface of the composite structure can have the largest porosity and theother exterior surface of the composite structure can have the smallestporosity. In embodiments, the composite structure can have a gradient ofporosity between the layers of nonwoven web, wherein the exteriorsurfaces of the composite structure can have the largest porosity andthe middle layer(s) of the composite structure can have the smallestporosity. In embodiments, the composite structure can include a fourthor higher layer of nonwoven webs such that a middle layer(s) can includethe second and third layers of nonwoven webs (for a four layer compositestructure), or the third layer of nonwoven web (for a five layercomposite structure).

Without intending to be bound by theory, it is believed that when theporosity of the composite structure comprises a gradient, the compositestructure advantageously has enhanced wicking of liquid from the moreporous exterior surface to the less porous exterior surface or lessporous middle layer(s).

The plurality of fibers in any given nonwoven layer of the compositearticle can be any of the fibers disclosed herein, and can be the sameor different. In embodiments, the composition of the fiber formingmaterials in the first plurality, second plurality, and third pluralityof fibers can be the same or different, for example, having anydifference in diameter, length, tenacity, shape, rigidness, elasticity,solubility, melting point, glass transition temperature (T_(g)), fiberforming material, color, or a combination thereof. The following Table 1demonstrates contemplated composite articles where the nonwoven layerscan include fibers having three different fiber compositions, whereineach letter “A”, “B”, and “C” refers to a specific fiber composition and“-” means that the contemplated composite article does not include athird layer of nonwoven web. Each of the fiber compositions A, B, and Ccan be (a) a single fiber type including a single fiber formingmaterial, (b) a single fiber type including a blend of fiber formingmaterials, (c) a blend of fiber types, each fiber type including asingle fiber forming material, (d) a blend of fiber types, each fibertype including a blend of fiber forming materials, or (e) a blend offiber types, each fiber type including a single fiber forming materialor a blend of fiber forming materials.

TABLE 1 Composite 1 Composite 2 Composite 3 Composite 4 Composite 5Composite 6 Composite 7 Composite 8 Composite 9 Composite 10 Composite11 Composite 12 Composite 13 Composite 14 Composite 15 Composite 16Composite 17 Composite 18 1^(st) plurality A A A B B B C C C A A A A A AA A A 2^(nd) plurality A B C A B C A B C A A A B B B C C C 3^(rd)plurality - - - - - - - - - A B C A B C A B C

TABLE 1 continued Composite 19 Composite 20 Composite 21 Composite 22Composite 23 Composite 24 Composite 25 Composite 26 Composite 27Composite 28 Composite 29 Composite 30 Composite 31 Composite 32Composite 33 Composite 34 Composite 35 Composite 36 1^(st) plurality B BB B B B B B B C C C C C C C C C 2^(nd) plurality A A A B B B C C c A A AB B B C C C 3^(rd) plurality A B C A B C A B C A B C A B C A B C

In embodiments, the first plurality of fibers includes water-solublepolyvinyl alcohol fiber forming material. In embodiments, the secondplurality of fibers includes water-soluble polyvinyl alcohol fiberforming material. In embodiments, the first plurality of fibers and thesecond plurality of fibers include water-soluble polyvinyl alcohol fiberforming material. In embodiments including a third layer of nonwoven webhaving a third plurality of fibers, the third plurality of fibers caninclude a water-soluble polyvinyl alcohol fiber forming material. Inembodiments, the polyvinyl alcohol fiber forming material can be presentin one or more fiber types in the plurality of fibers. The water-solublepolyvinyl alcohol fiber forming materials of any of the first plurality,second plurality, or third plurality of fibers can be any water-solublepolyvinyl alcohol fiber forming material disclosed herein. Inembodiments wherein two or more of the first plurality of fibers, thesecond plurality of fibers, and/or the third plurality of fibers includea polyvinyl alcohol fiber forming material, the polyvinyl alcohol can bethe same or different in each plurality, can be the sole fiber formingmaterial or part of blend of fiber forming material in each plurality,and if each plurality includes a different polyvinyl alcohol fiber, thedifference can be in length to diameter ratio (L/D), tenacity, shape,rigidness, elasticity, solubility, melting point, glass transitiontemperature (T_(g)), fiber chemistry, color, or a combination thereof.

In embodiments, the fibers of the first plurality of fibers, the secondplurality of fibers, and/or third plurality of fibers can include afiber forming material other than a polyvinyl alcohol fiber formingmaterial.

In embodiments, the first nonwoven web has a tenacity ratio (MD:CD) ofabout 0.5 to about 1.5. In embodiments, the first nonwoven web has aMD:CD of about 0.8 to about 1.25. In embodiments, the first nonwoven webhas a MD:CD of about 0.9 to about 1.1. In embodiments, the secondnonwoven web has a tenacity ratio (MD:CD) of about 0.5 to about 1.5. Inembodiments, the second nonwoven web has a MD:CD of about 0.8 to about1.25. In embodiments, the second nonwoven web has a MD:CD of about 0.9to about 1.1. In embodiments, the third nonwoven web has a tenacityratio (MD:CD) of about 0.5 to about 1.5. In embodiments, the thirdnonwoven web has a MD:CD of about 0.8 to about 1.25. In embodiments, thethird nonwoven web has a MD:CD of about 0.9 to about 1.1. Inembodiments, the nonwoven composite article has a tenacity ratio (MD:CD)in a range of about 0.5 to about 1.5, about 0.8 to about 1.25, about 0.9to about 1.1, or about 0.95 to about 1.05. In embodiments, the nonwovencomposite article has a MD:CD of about 0.8 to about 1.5. In embodiments,the nonwoven composite article has a MD:CD of about 0.9 to 1.1. TheMD:CD of the nonwoven composite article is related to the MD:CD ratio ofeach individual of layer of nonwoven web present in the compositearticle. Without intending to be bound by theory, it is believed thatthe MD:CD of the composite article cannot be determined by consideringthe MD and CD of each layer of nonwoven web individually, but the MD andCD of the nonwoven composite article must be measured. Without intendingto be bound by theory, it is believed that as the tenacity ratio MD:CDof the nonwoven composite article approaches 1, the durability of thecomposite article is increased, providing superior resistance tobreakdown of the nonwoven when stress is applied to the nonwoven duringuse. Further, without intending to be bound by theory, it is believedthat the MD:CD ratio of a composite article including at least one layerof a melt-spun nonwoven web will have an MD:CD ratio closer to 1:1 thanan identical composite article except including all carded layers.

The basis weights of the nonwoven composite articles of the disclosureare not particularly limiting and can be in a range of about 5 g/m² toabout 150 g/m², about 5 g/m² to about 125 g/m², about 5 g/m² to about100 g/m², about 5 g/m² to about 70 g/m², about 5 g/m² to about 50 g/m²,about 5 g/m² to about 30 g/m². In embodiments, the nonwoven compositearticles of the disclosure can have a basis weight of about 5 g/m² toabout 50 g/m². In embodiments, the nonwoven composite articles of thedisclosure can have a basis weight of about 50 g/m² to about 150 g/m².In embodiments, the first layer of nonwoven web can have a basis weightof about 30 g/m² to about 70 g/m² and the nonwoven composite article canhave a basis weight of about 60 g/m² to about 150 g/m². In embodiments,the first layer of nonwoven web can have a basis weight of about 5 g/m²to about 15 g/m². In embodiments, the first layer of nonwoven web canhave a basis weight of about 5 g/m² to about 15 g/m² and the nonwovencomposite article can have a basis weight in a range of about 15 g/m² toabout 50 g/m². In embodiments, the third layer of nonwoven web can havea basis weight of about 5 g/m² to about 15 g/m². In embodiments, thefirst layer of nonwoven web can have a basis weight of about 5 g/m² toabout 15 g/m² and the third layer of nonwoven web can have a basisweight of about 5 g/m² to about 15 g/m². In embodiments, the secondlayer of nonwoven web can be included in the composite article in about2.5 wt.% to about 10 wt.%, based on the total weight of the compositearticle. In embodiments, the second layer of nonwoven web can beincluded in the composite article in about 2.5 wt.% to about 10 wt.%,based on the total weight of the composite article and the first layerof nonwoven web can be included in the composite article in about 90wt.% to about 97.5 wt.%, based on the total weight of the compositearticle. In embodiments, the second layer of nonwoven web can beincluded in the composite article in about 2.5 wt.% to about 10 wt.%,based on the total weight of the composite article and the first layerof nonwoven web and the third layer of nonwoven web together areincluded in an about 90 wt.% to about 97.5 wt.%, based on the totalweight of the composite article. In embodiments, the third layer ofnonwoven web can be included in the composite article in about 2.5 wt.%to about 10 wt.%, based on the total weight of the composite article andthe first layer of nonwoven web and second layer of nonwoven webtogether are included in about 45 wt.% to about 48 wt.%, based on thetotal weight of the composite article.

In embodiments, the fiber diameters of the first plurality of fibers canbe substantially uniform. In embodiments, the fiber diameters of thesecond plurality of fibers can be substantially uniform. In embodiments,the fiber diameters of the third plurality of fibers can besubstantially uniform. In embodiments, the fiber diameters of the firstplurality of fibers and third plurality of fibers can be substantiallyuniform. In embodiments, the fiber diameters of each of the firstplurality of fibers, second plurality of fibers, and third plurality offibers can be substantially uniform.

In embodiments, the nonwoven composite article can have an improvedmodulus, tensile strength, elongation, tenacity, or a combinationthereof in the machine direction, cross direction, or both, relative toan identical article comprising only the first layer. In embodiments,the nonwoven composite article can have an improved modulus, tensilestrength, elongation, tenacity, or a combination thereof in the machinedirection, relative to an identical article comprising only the firstlayer. In embodiments, the nonwoven composite article can have animproved modulus, tensile strength, elongation, or a combination thereofin the cross direction, relative to an identical article comprising onlythe first layer. In embodiments, the nonwoven composite article can havean improved modulus, tensile strength, elongation, tenacity or acombination thereof in the machine direction and the cross direction,relative to an identical article comprising only the first layer.

Methods of Preparing Composite Articles

In general, the composite articles can be made using any process knownin the art suitable for combining two or more layers of nonwoven webssuch that at least a portion of the first layer and a portion of thesecond layer are fused, thereby forming an interface.

In embodiments, the method of forming the nonwoven composite articles ofthe disclosure can include the steps of:

-   (a) depositing on a first layer including a first nonwoven web, a    second layer comprising a second nonwoven web under conditions    sufficient to fuse at least a portion of the first nonwoven web to    at least a portion of the second nonwoven web, thereby forming a    first interface; and-   (b) optionally, depositing on the second layer comprising the second    nonwoven web, the third layer comprising the third nonwoven web    under conditions sufficient to fuse at least a second portion of the    second nonwoven web to at least a portion of the third nonwoven web,    thereby forming a second interface.

In embodiments, steps (a) and (b) can be repeated to include additionalnonwoven layers to the composite structure, e.g., a fourth nonwovenlayer, a fifth nonwoven layer, etc.

In general, the conditions sufficient to fuse at least a portion of thefirst nonwoven web to at least a portion of the second nonwoven weband/or to fuse at least a second portion of the second nonwoven web toat least a portion of the third nonwoven web can include thermal fusionand/or solvent fusion, as described herein.

In embodiments of the foregoing methods, the first layer can comprise acarded nonwoven web. In embodiments of the foregoing methods, the thirdlayer can comprise a carded nonwoven web or a melt-spun nonwoven web. Inembodiments of the foregoing methods, the second layer can include amelt-spun nonwoven web or an airlaid nonwoven web. In embodiments, thefirst layer can include a carded nonwoven web, the second layer caninclude a melt-spun nonwoven web, and the third layer can include acarded nonwoven web. In embodiments, the first layer can include acarded nonwoven web, the second layer can include a melt blown nonwovenweb, and the third layer can include a carded nonwoven web. Inembodiments, the second layer can include an airlaid nonwoven web. Inembodiments, the first layer can include a carded nonwoven web, thesecond layer can include an airlaid nonwoven web, and the third layercan include a melt-spun nonwoven web. In embodiments, the first layercan include a carded nonwoven web, the second layer can include anairlaid nonwoven web, and the third layer can include a melt blownnonwoven web. In embodiments, the nonwoven composite article can includefive layers of nonwoven web wherein the first layer can include a cardednonwoven web, the second layer can include an airlaid nonwoven web, thethird layer can include a melt-spun nonwoven web, the fourth layer caninclude an airlaid nonwoven web, and the fifth layer can included acarded nonwoven web. In embodiments, the nonwoven composite article caninclude five layers of nonwoven web wherein the first layer can includea carded nonwoven web, the second layer can include an airlaid nonwovenweb, the third layer can include a melt blown nonwoven web, the fourthlayer can include an airlaid nonwoven web, and the fifth layer canincluded a carded nonwoven web. In embodiments, the second nonwoven webcan include a cellulose fiber forming material.

Flushable Wipes

Flushable wipes of the disclosure can include a nonwoven web of thedisclosure and/or a composite article according to the disclosure.

Flushable wipes can include a plurality of fibers of the disclosure,wherein the plurality of fibers can include water soluble fibers and,optionally, water-insoluble fibers.

In embodiments wherein the flushable wipe includes a nonwoven webcomprising water-soluble fibers and water-insoluble fibers, the ratio ofwater-insoluble fiber to water-soluble fiber can range from about 1:18to about 4:1, about 1:10 to about 3:1, about 1:5 to about 2:1, or about1:2 to about 2:1, for example about 1:18, 1:16, 1:14, 1:12, 1:10, 1:5,1:3, 1:2, 1:1, 2:1, 3:1, or 4:1.

The flushable wipes of the disclosure can include a cleaning lotion.Flushable wipes of the disclosure generally include fibers having asurface energy that is high enough to allow the fibers to be readily wetby the cleaning lotion during the wetting step of the wipe manufacturingprocess. Thus, in embodiments, at least a portion of at least oneexterior layer of the nonwoven composite article of the flushable wipeincludes a hydrophilic fiber. In embodiments, at least a portion of eachexterior layer of the nonwoven composite article used to prepare theflushable wipe includes a hydrophilic fiber. As used herein, and unlessspecified otherwise, a “hydrophilic fiber” refers to any fiber having asurface thereof that is hydrophilic. A fiber can have a hydrophilicsurface when the fiber includes, for example, a hydrophilic fiberforming material, the fiber is a core-sheath type bicomponent fiberincluding a hydrophilic fiber forming material in the sheath, and/or thefiber has been surface treated to include a hydrophilic material on thesurface thereof. Without intending to be bound by theory, it is believedthat a hydrophilic fiber of a nonwoven can facilitate capillaryaction/wicking of a liquid from a surface of the nonwoven, providingimproved liquid acquisition relative to an identical nonwoven that doesnot include a hydrophilic fiber.

Non-limiting examples of applications for wipes include cleaningsurfaces, cleaning skin, automotive uses, baby care, feminine care, haircleansing, and removing or applying makeup, skin conditioners,ointments, sun-screens, insect repellents, medications, varnishes orindustrial and institutional cleaning.

Lotion Composition

The flushable wipes of the disclosure can comprise a lotion compositionto wet a substrate to facilitate cleaning. In embodiments wherein theflushable wipe is a personal care wipe, the lotion composition may alsoinclude ingredients to soothe, soften, or care for the skin, to improvethe feel of the lotion, to improve the removal of residues from theskin, to provide pleasant scents, and/or to prevent bacterial growth,for example.

Lotion compositions can have a pH at or near about 5.5, close to thephysiological skin pH. Low pH lotion compositions can have a pH at ornear about 3.8 and can be useful in cases where a wipe is being used toremove alkaline residues, such as residues from fecal matter, and helprestore a healthy acidic skin pH of approximately 5 and/or renderirritants from fecal matter non-irritating, as by inactivating fecalenzymes. Low pH lotions may also inhibit microbial growth. Inembodiments wherein the pH of the lotion composition is about 4 or less,the fibers of the first plurality of fibers, second plurality of fibers,and/or third plurality of fibers can include a polyvinyl alcoholcopolymer. The copolymer can be provided as the sole fiber formingmaterial in a fiber of a fiber blend or as one component of a fiberforming material in a fiber including a blend of fiber formingmaterials. In refinements of the foregoing embodiment, the fibers caninclude a blend of polyvinyl alcohol copolymers and homopolymers. Thepolyvinyl alcohol copolymers and homopolymers can be provided in a ratioof about 1:1 to about 4:1. In further refinements of the foregoingembodiments, the polyvinyl alcohol copolymer containing fibers can beblended with non-water-soluble fibers.

Lotion compositions can comprise a superwetter, a rheology modifier, anemollient and/or an emulsifier. The superwetter can be present in anamount of about 0.01% to 0.2% by weight of the superwetter to the totalweight of the lotion composition. The superwetter can be selected fromthe group consisting of trisiloxanes, polyether dimethicones wherein thepolyether functionality is PEG, PPG, or a mixture thereof, and a mixtureof the foregoing.

The rheology modifier can be present in an amount of about 0.01% to 0.5%by weight of the rheology based on the total weight of the lotioncomposition. The rheology modifier can be selected from the groupconsisting of xanthan gum, modified xanthan gum, and a combinationthereof.

The emollient, if present, may be a thickening emollient. Suitableemollients include, but are not limited to, PEG-10 sunflower oilglycerides, sunflower oil, palm oil, olive oil, emu oil, babassu oil,evening primrose oil, palm kernel oil, cod liver oil, cottonseed oil,jojoba oil, meadowfoam seed oil, sweet almond oil, canola oil, soybeanoil, avocado oil, safflower oil, coconut oil, sesame oil, rice bran oil,grape seen oil, mineral oil, isopropyl stearate, isostearylisononanoate, diethylhexyl fumarate, diisostearyl malate, triisocetylcitrate, stearyl stearate, methyl palmitate, methylheptyl isostearate,petrolatum, lanolin oil and lanolin wax, long chain alcohols like cetylalcohol, stearyl alcohol, behenyl alcohol, isostearyl alcohol, and2-hexyldecanol, myristyl alcohol, dimethicone fluids of variousmolecular weights and mixtures thereof, PPG-15 stearyl ether (also knownas arlatone E), shea butter, olive butter, sunflower butter, coconutbutter, jojoba butter, cocoa butter, squalene and squalene,isoparaffins, polyethylene glycols of various molecular weights,polypropylene glycols of various molecular weights, or mixtures thereof.

The emulsifier, if present, may be solid at room temperature. Suitableemulsifiers include, but are not limited to, laureth-23, ceteth-2,ceteth-10, ceteth-20, ceteth-21, ceteareth-20, steareth-2, steareth-10,steareth-20, oleth-2, oleth-10, oleth-20, steareth-100, steareth-21,PEG-40 sorbitan peroleate, PEG-8 stearate, PEG-40 stearate, PEG-50stearate, PEG-100 stearate, sorbitan laurate, sorbitan palmitate,sorbitan stearate, sorbitan tristearate, sorbitan oleate, sorbitantrioleate, polysorbate 20, polysorbate 21, polysorbate 40, polysorbate60, polysorbate 61, polysorbate 65, polysorbate 80, polysorbate 81,polysorbate 85, PEG-40 hydrogenated castor oil, citric acid ester,microcrystalline wax, paraffin wax, beeswax, carnauba wax, ozokeritewax, cetyl alcohol, stearyl alcohol, cetearyl alcohol, myristyl alcohol,behenyl alcohol, and mixtures thereof.

In embodiments, the cleaning lotion includes an aqueous emulsionincluding an emollient and an emulsifier.

The cleaning lotion can further comprise humectants including, but notlimited to glycerin, propylene glycol, and phospholipids; fragrancessuch as essential oils and perfumes as described herein; preservatives;enzymes; colorants; oil absorbers; pesticides; fertilizer; activators;acid catalysts; metal catalyst; ion scavengers; detergents;disinfectants; surfactants; bleaches; bleach components; and fabricsofteners. In embodiments, the cleaning lotion includes a fragrance,preservative, enzyme, colorant, oil absorber, pesticide, ion scavenger,detergent, disinfectant, or a combination thereof.

Preservatives prevent the growth of micro-organisms in the liquidlotion, the flushable wipe, and/or the substrate on which the wipe isused. Preservatives can be hydrophobic or hydrophilic. Suitablepreservatives include, but are not limited to parabens, such as methylparabens, propyl parabens, alkyl glycinates, iodine derivatives andcombinations thereof.

The lotion load can be between 150% and 480%. As used herein, “load”refers to combining a nonwoven web or composite article with a lotioncomposition, i.e., a lotion composition is loaded onto or into anonwoven web or composite article, without regard to the method used tocombine the nonwoven web or composite article with the lotioncomposition, i.e., immersion, spraying, kissrolling, etc. A “lotionload” refers to the amount of lotion loaded onto or into a nonwoven webor composite article, and is expressed as weight of the lotion to weightof the dry (unloaded) nonwoven web or composite article, as apercentage. It may be desirable for the flushable wipe to be loaded withlotion to a degree that some of the lotion can be easily transferred toa substrate (e.g., skin or another surface to be cleaned) during use.The transfer may facilitate cleaning, provide a pleasant sensation for auser (such as a smooth skin feeling or coolness from evaporation),and/or allow for the transfer of compounds to provide beneficialfunctions on substrate.

The flushable wipes can be nonwoven webs or composite articles having ahigh density of interstitial spaces between the fibers making up thewipe. In order to maintain enough lotion available on the surface of awipe to transfer to the substrate, much of the interstitial space in thewipe can be filled with lotion. The lotion in the interstitial space maynot be readily available for transfer to a substrate, such that excesslotion can be loaded into the wipe in an amount sufficient to signal tothe user that the lotion is available for transfer to a substrate, forexample, by providing an adequate sense of wetness. Advantageously,nonwoven composite articles used in the flushable wipes can have agradient of porosity as described herein, which can facilitate loadingof the lotion to the wipe.

The flushable wipe can be made by wetting a nonwoven web or compositearticle with at least 1 gram of liquid cleaning lotion per gram of dryfibrous composite. Suitable methods of delivering the cleaning lotion tothe nonwoven web or composite article include but are not limited tosubmersion, spraying, padding, extrusion coating and dip coating. Afterwetting, the wetted composite article can be folded, stacked, cut tolength, and packaged as desired. The flushable wipes are generally ofsufficient dimension to allow for a convenient handling while beingsmall enough to be easily disposed to the sewage system. The wettedcomposite article can be cut or folded to such dimensions during themanufacturing process or can be larger in size and having a means suchas perforations to allow individual wipes to be separated from the web,in a desired size, by a user.

In embodiments, the flushable wipes of the disclosure comprise anonwoven web of the disclosure and a cleaning lotion. In embodiments,the flushable wipes of the disclosure comprise a nonwoven compositearticle of the disclosure and a cleaning lotion. In embodiments, theflushable wipes of the disclosure consist of a nonwoven compositearticle of the disclosure and a cleaning lotion.

Absorbent Articles

The nonwoven webs and nonwoven composite articles of the disclosure canbe used as a liquid acquisition layer for absorbent articles. Theabsorbent articles can include bibs, breast pads, care mats, cleaningpads (e.g., floor cleaning pads), diapers, diaper pants, incontinenceliners, pads, and other articles (e.g., adult incontinence diapers,adult incontinence pads, adult incontinence pants, potty trainingliners, potty training pads, potty training pants, and pet training padse.g., puppy pads), interlabial devices, menstrual pads, panty liners,sanitary napkins, tampons, spill absorbing mats, spill absorbing pads,spill absorbing rolls, wound dressings, and the like. In one aspect, anyof the foregoing articles can be disposable items. The term “disposable”refers to articles which are designed or intended to be discarded aftera single use. That is, disposable articles are not intended to belaundered or otherwise restored or reused, and in embodiments may beincapable of laundering, restoration or reuse.

As used herein, the term “absorbent article” includes articles whichabsorb and contain liquids such as body exudates. The term “absorbentarticle” is intended to include diapers, incontinent articles, sanitarynapkins, and the like. The term “incontinent articles” is intended toinclude pads, undergarments (pads held in place by a suspension systemof some type, such as a belt, or the like), inserts for absorbentarticles, capacity boosters for absorbent articles, briefs, bed pads,and the like, regardless of whether they be worn by adults or otherincontinent persons. At least some of such absorbent articles areintended for the absorption of body liquids, such as menses or blood,vaginal discharges, urine, sweat, breast milk, and fecal matter.

As used herein “diapers” refers to devices which are intended to beplaced against the skin of a wearer to absorb and contain the variousexudates discharged from the body. Diapers are generally worn by infantsand incontinent persons about the lower torso so as to encircle thewaist and legs of the wearer. Examples of diapers include infant oradult diapers and pant-like diapers such as training pants. “Trainingpant”, as used herein, refers to disposable garments having a waistopening and leg openings designed for infant or adult wearers. A pantmay be placed in position on the wearer by inserting the wearer’s legsinto the leg openings and sliding the pant into position about awearer’s lower torso. A pant may be pre-formed by any suitable techniqueincluding, but not limited to, joining together portions of the articleusing refastenable and/or non-refastenable bonds (e.g., seam, weld,adhesive, cohesive bond, fastener, etc.). A pant may be pre-formedanywhere along the circumference of the article (e.g., side fastened,front waist fastened).

Absorbent articles of the disclosure will typically comprise a liquidpervious topsheet, a liquid impervious backsheet joined to the topsheet,and a liquid acquisition layer and an absorbent core between thetopsheet and backsheet. In embodiments wherein the absorbent article isa wearable article (e.g., incontinent articles, sanitary napkins, andthe like), the article can have a wearer facing side and an outer facingside. In general, the liquid pervious topsheet is on the wearer facingside and the liquid impervious backsheet is on the outer facing side ofthe absorbent article. The absorbent core is generally a sheet likestructure and, when provided as a wearable, has a wearer facing side andan outer facing side.

In general, the liquid pervious topsheet can be any liquid pervioustopsheet known in the art. For a wearable article, the topsheet can befully or partially elasticized or can be foreshortened to provide a voidspace between the topsheet and the absorbent core. In general, theliquid impervious backsheet can be any liquid impervious backsheet knownin the art. The backsheet prevents exudates absorbed by the absorbentcore and contained within the article form contacting any substrate theabsorbent article may be in contact with. The backsheet can beimpervious to liquids and include a laminate of a nonwoven and a thinplastic film, such as a thermoplastic film. Suitable backsheet filmsinclude those manufactured by Tredegar Industries Inc. of Terre Haute,Ind. and sold under the trade names X15306, X10962, and X10964. Othersuitable backsheet materials can include breathable materials thatpermit vapors to escape from the absorbent article, while stillpreventing liquid from passing through the backsheet. Exemplarybreathable materials can include materials such as woven webs, nonwovenwebs, and composite materials such as manufactured by Mitsui Toatsu Col,of Japan under the designation ESPOIR NO and by EXXON Chemical Co., ofBay City, Tex., under the designation EXXAIRE.

The absorbent core is disposed between the topsheet and the backsheet.The absorbent core can comprise any absorbent material that is generallycapable of absorbing and retaining liquids such as urine and other bodyexudates. The absorbent core can include a wide variety ofliquid-absorbent materials commonly used in disposable diapers and otherabsorbent articles such as super absorbent polymer, comminuted wood pulp(air felt), creped cellulose wadding; absorbent foams, absorbentsponges, absorbent gelling materials, or any other known absorbentmaterial or combinations of materials. The absorbent core can includeminor amounts (less than about 10%) of non-liquid absorbent materials,such as adhesives, waxes, oils and the like.

In general, the liquid acquisition layer includes a nonwoven web of thedisclosure including a plurality of fibers including a water-solublepolyvinyl alcohol fiber forming material. The plurality of fibers caninclude a single fiber type or a blend of fiber types, and the fiberscan include a sole polyvinyl alcohol fiber forming material or a blendof fiber forming materials including a polyvinyl alcohol fiber formingmaterial.

In embodiments, the liquid acquisition layer can be provided between theabsorbent core and the topsheet. In wearable embodiments, the liquidacquisition layer can be provided on the wearer facing side of theabsorbed core. In embodiments, the liquid acquisition layer can beprovided between the absorbent core and the backsheet. In wearableembodiments, the liquid acquisition layer can be provided on the outerfacing side of the absorbent core. In embodiments, the liquidacquisition layer is wrapped around the absorbent core. The liquidacquisition layer can be a single sheet that is wrapped around theabsorbent core or can be provided as two individual layers that arejoined. Without intending to be bound by theory, it is believed that byincluding the liquid acquisition layer between the absorbent core andthe backsheet or on the outer facing side of the absorbent coreadvantageously prevents leakage of the liquid from the absorbent articleby providing additional liquid acquisition material to catch anyoverflow of liquid from the topsheet side and/or wearer facing side.

In general, the liquid acquisition layer can be directly in contact withthe absorbent core, there can include a space between the absorbent coreand the liquid acquisition layer, or there can include an interveninglayer between the absorbent core and the liquid acquisition layer. Inembodiments, the liquid acquisition layer is in contact with theabsorbent core. In embodiments, the absorbent article includes anintervening layer provided between the acquisition layer and theabsorbent core. In embodiments, the liquid acquisition layer is incontact with the absorbent core on the topsheet side/wearer facing sideand an intervening layer is provided between the acquisition layer andthe absorbent core on the backsheet side/outer facing side. Inembodiments, the liquid acquisition layer is in contact with theabsorbent core on the backsheet side/outer facing side and anintervening layer is provided between the acquisition layer and theabsorbent core on the topsheet side/wearer facing side. The interveninglayer can be, for example, a second liquid pervious layer or liquidacquisition layer included to help facilitate spread of the liquid fromthe point of deposition to cover the full area of the absorbent core.

In embodiments, the absorbent article includes a liquid acquisitionlayer that is a nonwoven web of the disclosure. In embodiments, thewearable absorbent article includes a liquid acquisition layer that is anonwoven web of the disclosure. In embodiments, the absorbent articleincludes a liquid acquisition layer that is a nonwoven composite articleof the disclosure. In embodiments, the wearable absorbent articleincludes a liquid acquisition layer that is a nonwoven composite articleof the disclosure.

Dissolution and Disintegration Test (MSTM-205)

A nonwoven web, water-soluble film, or laminate structure can becharacterized by or tested for Dissolution Time and Disintegration Timeaccording to the MonoSol Test Method 205 (MSTM 205), a method known inthe art. See, for example, U.S. Pat. No. 7,022,656. The descriptionprovided below refers to a nonwoven web, while it is equally applicableto a water-soluble film or laminate structure.

Apparatus and Materials include:

-   600 mL Beaker,-   Magnetic Stirrer (Labline Model No. 1250 or equivalent),-   Magnetic Stirring Rod (5 cm),-   Thermometer (0 to 100° C. ± 1° C.),-   Template, Stainless Steel (3.8 cm x 3.2 cm),-   Timer (0 - 300 seconds, accurate to the nearest second),-   Polaroid 35 mm slide Mount (or equivalent),-   MonoSol 35 mm Slide Mount Holder (or equivalent), and-   Distilled water.

For each nonwoven web to be tested, three test specimens are cut from anonwoven web sample that is a 3.8 cm x 3.2 cm specimen. Specimens shouldbe cut from areas of web evenly spaced along the traverse direction ofthe web. Each test specimen is then analyzed using the followingprocedure.

Lock each specimen in a separate 35 mm slide mount.

Fill beaker with 500 mL of distilled water. Measure water temperaturewith thermometer and, if necessary, heat or cool water to maintain thetemperature at the temperature for which dissolution is beingdetermined, e.g., 20° C. (about 68° F.).

Mark height of column of water. Place magnetic stirrer on base ofholder. Place beaker on magnetic stirrer, add magnetic stirring rod tobeaker, turn on stirrer, and adjust stir speed until a vortex developswhich is approximately one-fifth the height of the water column. Markdepth of vortex.

Secure the 35 mm slide mount in the alligator clamp of the 35 mm slidemount holder such that the long end of the slide mount is parallel tothe water surface. The depth adjuster of the holder should be set sothat when dropped, the end of the clamp will be 0.6 cm below the surfaceof the water. One of the short sides of the slide mount should be nextto the side of the beaker with the other positioned directly over thecenter of the stirring rod such that the nonwoven web surface isperpendicular to the flow of the water.

In one motion, drop the secured slide and clamp into the water and startthe timer. Rupture occurs when the sample has become compromised withinthe slide, for example, when a hole is created. Disintegration occurswhen the nonwoven web breaks apart and no sample material is left in theslide. When all visible nonwoven web is released from the slide mount,raise the slide out of the water while continuing to monitor thesolution for undissolved nonwoven web fragments. Dissolution occurs whenall nonwoven web fragments are no longer visible and the solutionbecomes clear. Rupture and dissolution can happen concurrently fornonwoven samples wherein the fibers are prepared from polyvinyl alcoholhaving a low degree of hydrolysis (e.g., about 65-88%). Dissolutiontimes are recorded independently of rupture times when there is a 5second or greater difference between rupture and dissolution.

Thinning time can also be determined using MSTM-205. Thinning of anonwoven web occurs when some of the fibers making up the nonwoven webdissolve, while other fibers remain intact. The thinning of the weboccurs prior to disintegration of the web. Thinning is characterized bya decrease in opacity, or increase in transparency, of the nonwoven web.The change from opaque to increasingly transparent and can be visuallyobserved. During MSTM-205, after the secured slide and clamp have beendropped into the water the opacity/transparency of the nonwoven web ismonitored. At the time point wherein no change in opacity/transparencyis observed (i.e., the web does not become any less opaque or moretransparent), the time is recorded as the thinning time.

The results should include the following: complete sampleidentification; individual and average disintegration and dissolutiontimes; and water temperature at which the samples were tested.

Method for Determining Single Fiber Solubility

The solubility of a single fiber can be characterized by the waterbreaking temperature. The fiber breaking temperature can be determinedas follows. A load of 2 mg/dtex is put on a fiber having a fixed lengthof 100 mm. Water temperature starts at 1.5° C. and is then raised by1.5° C. increments every 2 minutes until the fiber breaks. Thetemperature at which the fiber breaks is denoted as the water breakingtemperature.

The solubility of a single fiber can also be characterized by thetemperature of complete dissolution. The temperature of completedissolution can be determined as follows. 0.2 g of fibers having a fixedlength of 2 mm are added to 100 mL of water. Water temperature starts at1.5° C. and is then raised by 1.5° C. increments every 2 minutes untilthe fiber completely dissolves. The sample is agitated at eachtemperature. The temperature at which the fiber completely dissolves inless than 30 seconds is denoted as the complete dissolution temperature.

Diameter Test Method

The diameter of a discrete fiber or a fiber within a nonwoven web isdetermined by using a scanning electron microscope (SEM) or an opticalmicroscope and an image analysis software. A magnification of 200 to10,000 times is chosen such that the fibers are suitably enlarged formeasurement. When using the SEM, the samples are sputtered with gold ora palladium compound to avoid electric charging and vibrations of thefiber in the electron beam. A manual procedure for determining the fiberdiameters is used from the image (on monitor screen) taken with the SEMor the optical microscope. Using a mouse and a cursor tool, the edge ofa randomly selected fiber is sought and then measured across its width(i.e., perpendicular to the fiber direction at that point) to the otheredge of the fiber. A scaled and calibrated image analysis tool providesthe scaling to get an actual reading in microns. For fibers within anonwoven web, several fibers are randomly selected across the sample ofnonwoven web using the SEM or the optical microscope. At least twoportions of the nonwoven web material are cut and tested in this manner.Altogether at least 100 such measurements are made and then all data arerecorded for statistical analysis. The recorded data are used tocalculate average (mean) of the fibers, standard deviation of thefibers, and median fiber diameters.

Tensile Strength, Modulus, and Elongation Test

A nonwoven web, water-soluble film, or laminate structure characterizedby or to be tested for tensile strength according to the TensileStrength (TS) Test, modulus (or tensile stress) according to the Modulus(MOD) Test, and elongation according to the Elongation Test is analyzedas follows. The description provided below refers to a nonwoven web,while it is equally applicable to a water-soluble film or laminatestructure. The procedure includes the determination of tensile strengthand the determination of modulus at 10% elongation according to ASTM D882 (“Standard Test Method for Tensile Properties of Thin PlasticSheeting”) or equivalent. An INSTRON tensile testing apparatus (Model5544 Tensile Tester or equivalent) is used for the collection ofnonwoven web data. A minimum of three test specimens, each cut withreliable cutting tools to ensure dimensional stability andreproducibility, are tested in the machine direction (MD) (whereapplicable) for each measurement. Tests are conducted in the standardlaboratory atmosphere of 23 ± 2.0° C. and 35 ± 5 % relative humidity.For tensile strength or modulus determination, 1″-wide (2.54 cm) samplesof a nonwoven web are prepared. The sample is then transferred to theINSTRON tensile testing machine to proceed with testing while minimizingexposure in the 35% relative humidity environment. The tensile testingmachine is prepared according to manufacturer instructions, equippedwith a 500 N load cell, and calibrated. The correct grips and faces arefitted (INSTRON grips having model number 2702-032 faces, which arerubber coated and 25 mm wide, or equivalent). The samples are mountedinto the tensile testing machine and analyzed to determine the 100%modulus (i.e., stress required to achieve 100% film elongation), tensilestrength (i.e., stress required to break film), and elongation % (samplelength at break relative to the initial sample length). In general, thehigher the elongation % for a sample, the better the processabilitycharacteristics for the nonwoven web (e.g., increased formability intopackets or pouches).

Determination of Basis Weight

Basis weight is determined according to ASTM D3776/D3776M-09a (2017).Briefly, a nonwoven specimen having an area of at least 130 cm² or anumber of smaller die cut specimens taken from different locations inthe sample and having a total area of at least 130 cm² are cut. Thespecimen(s) are weighed to determine mass on a top loading analyticalbalance with a resolution of ± 0.001 g. The balance is protected fromair drafts and other disturbances using a draft shield. Specimens offabric may be weighed together. The mass is calculated in ounces persquare yard, ounces per linear yard, linear yards per pound, or gramsper square meter to three significant figures.

Determination of Moisture Vapor Transmission Rate

Moisture Vapor Transmission Rate (MVTR) is determined according toMSTM-136. The MVTR defines how much moisture per day moves through asample. The description provided below refers to a nonwoven web, whileit is equally applicable to a water-soluble film or laminate structure.

Apparatus and Materials include:

-   Permatran-W Model 3/34 (or equivalent),-   Compressed Gas Cylinder of Nitrogen (99.7% or above),-   Regulator-Tee (part number 027-343),-   Main Line Supply regulator,-   HPLC Grade Water (or equivalent),-   10 cc Syringe with Luerlok Tip (part number 800-020),-   Powder-free gloves,-   High vacuum grease (part number 930-022),-   (2) Test Cells,-   Cutting template,-   Cutting board,-   Razor blade with handle, and-   Cut-resistant glove.

Preparation of the Permatran W-Model 3/34: Make sure nitrogen pressurelevel is above 300 psi, the pressure on the carrier gas regulator-teereads 29 psi (must not exceed 32 psi) and the main line supply regulatorpressure is set to 35 psi. Open the door on the instrument panel toaccess humidifier to check the water level. If water level is low, filla syringe with HPLC-grade water and insert the leur fitting on thesyringe into the “fill Port” for the reservoir. Open the “Fill Valve” byturning it 2-3 turns counterclockwise then push in the plunger on thesyringe to force the water into the reservoir. Close the ‘Fill Valve″and remove syringe. Note: do not allow water level to exceed line markedadjacent to reservoir.

Preparation and Testing of Samples: For each nonwoven web to be tested,take the sample web and lay it flat on the cutting board. Place thetemplate on top of the web and use the razor blade with a handle to cutout the sample. Make sure cut-resistant glove is worn when cutting thesample out. Set the sample aside. Grease around the sealing surfaces ofthe test cell’s top piece with high vacuum grease. Mount the film sampleon top of the test cell’s top piece. Note: Orientation can be important.If a homogeneous material, orientation is not critical. If amulti-layered and laminated material, place the multilayered film orlaminate with barrier coating or laminate up, towards the top of thecell. For example, a one-side, wax coated PVOH web should be mountedwith the wax side up, placing the wax towards the carrier gas(Nitrogen). Place the test cell’s top piece on top of the test cell’sbottom piece. Make sure the test cell is clamped together with a goodseal. Press the cell load/unload button to open cell tray. Grasp thetest cell by the front and back edges and lower it straight down. Closethe cell tray completely by gently pushing straight towards panel. Pressthe cell load/unload button to clamp the cell. Note: You should hear aclick. Repeat for second sample.

After the samples are loaded and the instrument is ready, the testparameters must be set. Note: There are two types of test parameters,cell parameters and instrument parameters. Cell parameters are specificto each cell while instrument parameters are common for all cells. Touchthe “Test Button” on the screen. Under “Auto Test” select “Tab A”. Touch“Cell Tab”. Fill out the following by touching each bubble: ID, Area(cm²), Thickness (mil). Note: Area of template is 50 cm². Repeat for“Tab B”. Touch “Instrument Tab”. Fill out the following by touching eachbubble: Cell Temp (°C) and Test Gas RH (%). Note: Make sure 100% RH isset to off. Cell temperature can be set to a minimum of 10° C. tomaximum of 40° C. Test Gas RH can be set to minimum 5% to 90%. If 100%RH is needed, it requires a different method. Repeat for “Tab B”. Oncethe test parameters are set, select “Start Selected” or “Start All”depending on sample number. Note: The indicator light for each cell onfront panel will be green indicating the start of test.

Surface Resistivity Measurements

Surface resistivity of nonwoven webs and films can be measured accordingto ASTM D257.

Softness Rating

The hand feel of a nonwoven web or pouch of the disclosure is related tothe softness of the sample and can be evaluated using relative testingmethods. A tester carrying out the softness evaluation uses clean handsto feel the samples in whatever manner or method the individual chose,to determine a softness rating for the nonwoven webs and articles of thedisclosure as compared to a control material comprising a nonwoven webconsisting of fibers consisting of polyvinyl alcohol homopolymers havinga degree of hydrolysis of 88%, the fibers having a 2.2 dtex / 51 mm cut,having a softness rating of 1 (softest) and a control materialcomprising a nonwoven web consisting of fibers consisting of 75%polyvinyl alcohol homopolymers having a degree of hydrolysis of 88%, thefibers having a 2.2 /51 mm cut, and 25% of 22 dtex / 38 mm PET fiber,having a softness rating of 5 (roughest/ coarsest). The hand panel is ablind study so that the raters are not swayed by their perception ofsample names. Samples were rated from 1 to 5.

Flushability Test

The ability of the nonwoven webs and/or laminates of the disclosure tobe flushed in a septic or municipal sewage treatment system can bedetermined according to a modified INDA/EDANA - Criteria for Recognitionas a Flushable Product, as provided below. The below test referencesnonwoven web samples, however it will be understood that the method canalso be used for laminate structures.

Equipment and materials include:

-   Rocking digital platform shaker,-   Two clear, plastic, 12 x 5 x 3.9 inch containers,-   Two sieves (12.5 mm apertures),-   Dried nonwoven web samples, and-   100° C. oven.

Parameters include:

-   Rocking platform set to 18 RPM and 11° tilt period,-   1L tap water per container, and-   30 min testing period.

Testing Procedure:

-   1. Place two containers on rocking platform. This method tests two    samples at a time.-   2. Measure 1 L of tap water in beaker and pour into one plastic    container. Repeat for other container. Make sure tap water in    containers is at 15° C. ± 1° C. before starting test.-   3. Record weight of the initial dried test sample (initial sample    mass (g)) and weight of sieves (initial sieve mass (g)) and record    independently.-   4. Set appropriate parameters on digital rocking platform.-   5. Place each test sample in their corresponding container and    immediately start the agitation process (rocking of the platform),-   6. Once the process is complete (after 30 minutes), take each    container and pour through their corresponding sieves. Pouring at a    height of 10 cm above sieve plate.-   7. Rinse container into sieve to ensure all of the remaining test    sample was removed.-   8. Place sieve in 100° C. oven for 45 minutes to ensure all water    evaporates.-   9. Record weight of sieve and remaining test sample together (total    final mass (g)).-   10. Calculate the total retained sample mass (final sample mass    (g)):-   Final sample mass (g) = total final mass (g) − initial sieve mass (g)-   11. Calculate the percent (%) disintegration:-   $\begin{array}{l}    {\%\mspace{6mu}\text{disintegration}\mspace{6mu} =} \\    {\left\lbrack {1 - \left( {\text{final sample mass}\left( \text{g} \right)\mspace{6mu}/\mspace{6mu}\text{initial sample mass}\left( \text{g} \right)} \right)} \right\rbrack\mspace{6mu} \times \mspace{6mu} 100}    \end{array}$-   12. Make sure sieves are cleaned, dried, and re-weighed before    starting next test.-   13. Repeat test until replicate of N=3 is complete for each specific    test sample.

A sample is sufficiently flushable to be disposed of by flushing in aseptic or municipal sewage treatment system when the sample has apercent disintegration equal to or greater than of at least 20%. Inembodiments, the nonwoven webs, laminates, and pouches of the disclosurecan have a percent disintegration of at least 20%, at least 30%, atleast 35%, at least 40%, at least 45%, at least 50%, at least 55%, atleast 60%, at least 65%, at least 70%, at least 75%, at least 80%, atleast 85%, at least 90%, or at least 95% as measured by the FlushabilityTest.

Liquid Release Test

FIG. 4 is an illustration of a wire frame cage (shown with the top open,to better illustrate water-soluble pouches contained therein) for use inthe Liquid Release Test described herein.

FIG. 5 shows an apparatus for performing the Liquid Release Test,including a beaker resting on a stand, the stand holding a rod forlowering a cage into the beaker, the rod being fixable by a collar witha set screw (not shown).

A water-soluble nonwoven web, film, and/or pouch characterized by or tobe tested for delayed solubility according to the Liquid Release Test isanalyzed as follows using the following materials:

-   2L beaker and 1.2 liters of deionized (DI) water;-   Water-soluble pouch to be tested; the pouch is pre-conditioned for    two weeks at 38° C.; for results to be comparative, all nonwoven    webs tested should have the same basis weight and all films tested    should have the same thickness, for example, 88 µm or 76 µm;-   Thermometer;-   Wire cage; and-   Timer.

Before running the experiment, ensure that enough DI water is availableto repeat the experiment five times, and ensure that the wire cage andbeaker are clean and dry.

The wire frame cage is a plastic coated wire cage (4″ X 3.5” X 2.5”)with no sharp edges, or equivalent. The gauge of the wire should beabout 1.25 mm and the wire should have openings the size of 0.5 inch(1.27 cm) squares. An example image of a cage 28 with test pouches 30 isshown in FIG. 4 .

To set up for the test, carefully place the water-soluble pouch in thecage while not scratching the pouch on the cage and allowing free spacefor the pouch to move. Do not bind the pouch tightly with the wire cage,while still ensuring it is secure and will not come out of the cage. Theorientation of the pouch in the cage should be such that the naturalbuoyancy of the pouch, if any, is allowed (i.e. the side of the pouchthat will float to the top should be placed towards the top). If thepouch is symmetrical, the orientation of the pouch generally would notmatter.

Next, fill the 2 L beaker with 1200 milliliters of 20° C. DI water.

Next, lower the wire frame cage with the enclosed pouch into the water.Ensure that the cage is 1 inch (2.54 cm) from the bottom of the beaker.Be sure to fully submerge the pouch on all sides. Ensure that the cageis stable and will not move and start a timer as soon as the pouch islowered into the water. The position of the cage with respect to thewater in the beaker can be adjusted and maintained by any suitablemeans, for example by using a clamp fixed above the beaker, and a rodattached to the top of the cage. The clamp can engage the rod to fix theposition of the cage, and tension on the clamp can be lowered in orderto lower the cage into the water. Other means of frictional engagementcan be used in the alternative to a clamp, for example a collar with aset screw, as shown in FIG. 5 (set screw not shown). FIG. 5 shows abeaker resting on a stand, the stand holding a rod for lowering a cage(not shown) into the beaker, the rod being able to hold a fixed verticalposition by use of a collar having a set screw (not shown) that engagesthe rod, for example by friction or by engagement with a hole (notshown) in the rod.

Liquid content release is defined as the first visual evidence of theliquid leaving the submerged pouch.

Determination of the Degree of Hydrolysis of a Fiber

Titration Method. The degree of hydrolysis of a fiber can be determinedusing titration. In particular, a known amount of polyvinyl alcoholfibers are dissolved in 200 mL of deionized water by agitation andheating the mixture at a temperature higher than 70° C. Once all of thePVOH has dissolved, the solution is cooled to room temperature. Once thesolution has cooled, 4-5 drops of phenolphthalein indicator solution areadded to the PVOH solution, along with 20.0 mL of 0.5 N NaOH solution.The solution is mixed and left at room temperature for a minimum of 2hours. After this time, 20.0 mL of 0.5 N sulfuric acid are added to thesolution and mixed. The solution is titrated with 0.1 N NaOH solutionuntil the endpoint, which is taken as the point at which the solutionturns faint pink and maintains this color without returning to acolorless solution for a minimum of 30 seconds. Using the measurementsobtained in the aforementioned procedure, the DH of the PVOH isdetermined via the following calculations

$A_{1}\mspace{6mu} = \mspace{6mu}\frac{\left( {V_{sample}\mspace{6mu} - \mspace{6mu} V_{blank}} \right)\mspace{6mu} \times \mspace{6mu} N\mspace{6mu} \times \mspace{6mu} 0.06005}{Wt_{sample}\mspace{6mu} \times \mspace{6mu}\frac{P}{100}} \times \text{100}$

$A_{2}\mspace{6mu} = \mspace{6mu}\frac{44.05\mspace{6mu} \times \mspace{6mu} A_{1}}{60.05\mspace{6mu} - \mspace{6mu}\left( {0.42\mspace{6mu} \times \mspace{6mu} A_{1}} \right)}$

DH = 100 − A₂

where:

-   A1: residual acetate groups (wt %),-   A2: residual acetate groups (mole %),-   DH: degree of hydrolysis (mole %),-   Vsample: volume of 0.1 N NaOH solution added during titration of    sample (mL),-   Vblank: volume of 0.1 N NaOH solution added during titration of    blank (mL),-   N: certified concentration of standardized 0.1 N NaOH solution used    in titration step Wtsample: sample mass (g), and-   P: purity of PVOH sample = 100 - (volatile matter (wt %) + sodium    acetate (wt %)).

FTIR Method. FTIR can be used to determine the degree of hydrolysis ofthe outer portion of a fiber surface via attenuated total reflectance(ATR). The depth of the fiber which this method measures is dependent onthe specific ATR apparatus, in particular, the crystal used. By takingthe ratio of the peak heights at ~1730 cm⁻¹ (ketone peak, attributed toresidual acetate groups) and ~1420 cm⁻¹ (reference peak), one can usethe equation obtained by plotting the same ratios for PVOH resinsagainst known degrees of hydrolysis to determine the degree ofhydrolysis of the unknown sample.

Gradient Test Method. A gradient in the degree of hydrolysis of a fibercan be determined and quantified using cross-section X-ray photoelectronspectroscopy (XPS), depth XPS, NMR techniques, ultraviolet photoelectronspectrometry (UPS), environmental SCM, or Auger electron spectroscopy(AES or SAM).

For XPS analysis, the depth of the fiber which this method measures isdependent on the specific ion beam used during the XPS analysis fordepth profiling to determine changes in degree of hydrolysis as afunction of cross section. By taking the ratio of the deconvoluted peaksat 287.6 eV and 288.8 eV, representing the carboxyl and carbonyl groupsof acetate groups for non-fully hydrolyzed PVOH, to that of 286.5 eV and532.8 eV, corresponding to the hydroxyl groups of PVOH, one can use theequation obtained by plotting the same ratios for PVOH resins againstknown degrees of hydrolysis to determine the degree of hydrolysis of theunknown sample. This method can be repeated between ion beam sputteringstages to gain a complete depth profile and change of degree ofhydrolysis across the cross-section of the PVOH fibers. XPS methods aredescribed in Gilbert et al “Depth-profiling X-ray photoelectronspectroscopy (XPS) analysis of interlayer diffusion in polyelectrolytemultilayers” PNAS, vol. 110, no. 17, 6651-6656 (2013) (available:https://www.pnas.org/content/pnas/1/10/17/6651.full.pdf, and EuropeanPolymer Journal 126 (2020) 109544, the entirety of which are herebyincorporated by reference.

AES methods are described in ASTM E984-12, the entirety of which ishereby incorporated by reference.

Measurement of Fiber Shrinkage (%)

A MonoSol Standard Operating Procedure is used to measure a shrinkage ofa fiber along a longitudinal axis of the fiber while contacting water ata temperature in a range of from 10° C. to 23° C.

Materials include:

-   Fiber samples (approximately 3 grams),-   500 mL beaker,-   Chilled deionized water (located in a refrigerator),-   Deionized water,-   Paper clip,-   Alligator clamp (solubility stand),-   Stir plate, and-   Timer.

A sample is prepared through the following steps:

-   obtain a small bundle of fibers (approximate weight of 0.013    gram (g) - 0.015 g) that is not entangled to ensure that the fibers    of the small bundle will hold in the paper clip and the alligator    clamp;-   take a paper clip and pull an end of the fiber through the cross    sections of the paper clip; and-   do so for each fiber that needs to be tested, with a replicate of N    = 3 for each testing temperature, e.g., 23° C. and 10° C.

The testing apparatus as shown in FIG. 8 is set up as follows:

-   fill a 500 mL beaker with 400 mL of water of a respective    temperature while the water temperature is checked using a    temperature probe before and during testing; and-   tape a ruler to the top of the alligator clamp such that the ruler    hangs parallel to the clamp;-   Place the beaker on a stir plate and a solubility stand next to the    stir plate, submerging the ruler into the beaker such that a length    of the fiber can be read.

The testing procedure includes the following steps:

-   attach the free end of the paper clipped fiber into the alligator    clamp;-   submerge the test sample into the beaker so that it’s lined up next    to the ruler;-   start the timer and record the initial length of the fiber. The test    sample fiber length is from the end of alligator clip to the top of    the paper clip (as shown in FIG. 8 );-   after two minutes, record the final length of the fiber; and-   lift the clamp out of the water and remove the sample fiber from the    clamp. Be sure to thoroughly dry off the outside and the inside of    clamp between each test.

The shrinkage of a fiber is calculated using the following equation:

shrinked length = initial length − final length

$\frac{shrinked\mspace{6mu} length}{initial\mspace{6mu} length}\mspace{6mu} \times \mspace{6mu} 100\%\mspace{6mu} = \mspace{6mu} fiber\mspace{6mu} shrinkage\mspace{6mu}(\%)$

After contacting water, a fiber provided in the present disclosureabsorbs water and swells in the traverse cross-section, while displayinga shrinkage in its length along the longitudinal direction.

One or more optional features that can be used individually or incombination are described in the following paragraphs. Optionally, thefiber to be treated is a polyvinyl acetate fiber. Optionally, the fiberto be treated is a polyvinyl alcohol fiber. Optionally, the fiber to betreated is a polyvinyl alcohol fiber comprising a polyvinyl alcoholpolymer having a degree of hydrolysis in a range of 79-99%. Optionally,the fiber to be treated is a polyvinyl alcohol fiber comprising apolyvinyl alcohol polymer having a degree of hydrolysis in a range of88%-96%. Optionally, the fiber to be treated is a polyvinyl alcoholfiber comprising a polyvinyl alcohol polymer having a degree ofhydrolysis of 88%, 92%, or 96%. Optionally, the fiber to be treated is apolyvinyl alcohol fiber comprising a polyvinyl alcohol copolymer.Optionally, the fiber to be treated is a polyvinyl alcohol fibercomprising an anionically modified comopolymer. Optionally, the fiber tobe treated is a polyvinyl alcohol fiber comprising a polyvinyl alcoholcopolymer and an anionically modified PVOH copolymer.

Optionally, the hydrolysis agent comprises a hydroxide salt selectedfrom the group consisting of sodium hydroxide, potassium hydroxide,ammonium hydroxide, and a combination thereof. Optionally, thehydrolysis agent comprises sodium hydroxide. Optionally, the hydrolysisagent comprises potassium hydroxide. Optionally, the solvent of thehydrolysis agent solution comprises methanol. Optionally, the solvent ofthe hydrolysis agent solution comprises methanol and water. Optionally,the solvent of the hydrolysis agent solution comprises DMSO and water.Optionally, the solvent of the hydrolysis agent solution comprises analcohol that is a liquid under the treatment conditions.

Optionally, the admixing of the fiber to be treated and the hydrolysisagent solution comprises immersing the fiber in the hydrolysis agentsolution. Optionally, the admixing comprises heating the mixture of thefiber and the hydrolysis agent solution. Optionally, the admixingcomprises heating the mixture of the fiber and the hydrolysis agentsolution to a temperature of about 30° C. to about 60° C. Optionally,the admixing comprises heating the mixture of the fiber and thehydrolysis agent for up to about one hour. Optionally, the admixingcomprises heating the mixture of the fiber and the hydrolysis agent forabout 1 hour to about 6 hours. Optionally, the admixing comprisesheating the mixture of the fiber and the hydrolysis agent for about 6hours to about 24 hours.

Optionally, the fiber to be treated can be contacted with the hydrolysisagent solution to increase the degree of hydrolysis of a hydrolyzablepolymer of the fiber in a region of the fiber comprising at least thesurface of the fiber. Optionally, the contacting can be by immersion.Optionally, the contacting can be by dip-coating. Optionally, thecontacting can be by spraying. Optionally, the contacting can be bybrushing. Optionally, the contacting can be by rolling.

In some embodiments, the hydrolysis agent solution comprises sodiumhydroxide and methanol, the admixing step comprises immersing the fiberin the hydrolysis agent solution, and the mixture of the fiber in thehydrolysis agent solution is heated to a temperature of about 30° C. to60° C. for about 1 minute to about 24 hours. The fiber comprises apolymer comprising at least one of a vinyl acetate moiety or a vinylalcohol moiety and having a degree of hydrolysis less than 100% asdescribed herein. For example, in some embodiments, the fiber comprisesa copolymer of vinyl alcohol and vinyl acetate having a degree ofhydrolysis of 88%, 92%, or 96% or an anionically modified copolymerhaving a carboxylate or sulfonate modification having a degree ofhydrolysis of 88%, 92%, or 96%. The hydrolysis agent solution comprisessodium hydroxide and methanol. The admixing comprises immersing thefiber in the hydrolysis agent solution, and the mixture of the fiber inthe hydrolysis agent solution is heated to a temperature of about 30° C.to 60° C. for a time period, for example, from about 12 hours to about24 hours, or from about 1 hour to about 12 hours, or from about oneminute to about 1 hour.

An hydrolysis reaction of a copolymer of vinyl acetate and vinyl alcoholis illustrated in Scheme (1) as follows:

Such a copolymer is a polyvinyl alcohol copolymer, and can be a modifiedpolyvinyl alcohol copolymer as described herein.

The present disclosure also provides a particle having a core-sheathstructure or also referred to as a core-shell structure, and methods ofmaking such a particle. The present disclosure including thecompositions and the methods with respect to fibers are also applicableto particles. The term “particle” as used herein is understood toencompass any product in a particulate form, which may have any suitableshape and/or any suitable size. In embodiments, the particle may have aregular or uniform shape. e.g., spherical, cube, cuboid, cylinder,ellipsoid, or an irregular shape. In embodiments, the particle size maybe at micron level or millimeter level. For example, the particle mayhave any suitable form, such as a bead, a microsphere, or a powder form.In some embodiments, the particle may have a size in a range of fromabout 1 micron to about 1,000 microns, for example, from about 5 micronsto about 100 microns, from about 10 microns to about 100 microns, fromabout 2 microns to about 10 microns, or any other suitable size orrange. In some embodiments, the particle may have a size in a range offrom about 1 millimeter (mm) to about 10 mm, for example, from about 1mm to 5 mm, from about 1 mm to 2 mm, or any other suitable size orrange.

In embodiments, the particle has a core-shell structure including a coreregion and a shell region at least partially covering, encompassing, orsurrounding the core region. The core region includes a polymercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety having a first degree of hydrolysis less than 100% as describedherein. In example embodiments, the shell region is disposed radiallyoutward from the core region. The shell region includes the polymercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety and having a second degree of hydrolysis greater than the firstdegree of hydrolysis. In some embodiments, the particle has anincreasing gradient in a degree of hydrolysis of the polymer extendingradially from a center of the core region to an exterior surface of theshell region. As described herein, the polymer comprising at least oneof a vinyl acetate moiety or a vinyl alcohol moiety comprises apolyvinyl alcohol homopolymer, a polyvinyl acetate homopolymer, apolyvinyl alcohol copolymer, a modified polyvinyl alcohol copolymer, orcombinations thereof. For example, the polyvinyl alcohol copolymer is acopolymer of vinyl acetate and vinyl alcohol in some embodiments. Thepolyvinyl alcohol copolymer may be anionically modified to furtherinclude a carboxylate, a sulfonate, or combinations thereof.

In embodiments, a method for making a particle having a core-shellstructure includes at least one step of admixing a particle (or acertain amount of particles) comprising a hydrolyzable polymer asdescribed herein with a hydrolysis agent solution to form a mixture soas to increase the degree of hydrolysis in a surface region, e.g., theshell region, of the particle. The polymer comprises at least one of avinyl acetate moiety or a vinyl alcohol moiety and has a degree ofhydrolysis less than 100%. In embodiments, the particle has a uniformcomposition. The resulting particle has a core-shell structure includinga core region and a shell region (or the surface region). As describedherein, the hydrolysis agent solution comprises a hydrolysis agent and asolvent. The mixture of the particle and the hydrolysis agent solutionmay be heated. The hydrolysis agent solution is admixed under conditionssufficient to provide at least one of a predetermined degree ofhydrolysis or a predetermined an increasing gradient in the degree ofhydrolysis increase from a center of the particle to an exterior surfaceof the particle. The particle may be admixed with the hydrolysis agentsolution at a temperature in a range of about 10° C. to about 100° C.for a period of time in a range of from about 1 minute to about 48 hoursas described above. The polymer may have a degree of hydrolysis greaterthan about 79% and less than about 96% prior to the step of admixing.The polymer in the sheath region has a second degree of hydrolysis in arange of from about 88% to about 96% after the step of admixing. Theresulting particle is water-soluble after the step of admixing.

In another aspect, the present disclosure also provides threedimensional articles having a core-sheath structure or also referred toas a core-shell structure including a surface region, i.e., the sheathregion, and a core region, and methods of making such an article. Thepresent disclosure including the compositions and the methods withrespect to fibers or particles are also applicable to any threedimensional article. The sheath region includes the polymer comprisingat least one of a vinyl acetate moiety or a vinyl alcohol moiety andhaving a second degree of hydrolysis greater than the first degree ofhydrolysis for the polymer in the core region. In some embodiments, thearticle has an increasing gradient in a degree of hydrolysis of thepolymer extending from a center of the core region to an exteriorsurface of the sheath region. The articles may have any suitable sizeand shape, and can be disposable after use and dissolvable in water.

The following paragraphs describe further aspects of the disclosure.

1. A fiber having a surface region and an interior region, the fibercomprising: a polymer comprising at least one of a vinyl acetate moietyor a vinyl alcohol moiety, the fiber having a transverse cross-sectionincluding the interior region comprising the polymer having a firstdegree of hydrolysis and the surface region comprising the polymerhaving a second degree of hydrolysis greater than the first degree ofhydrolysis.

2. The fiber according to clause 1, wherein the transverse cross-sectionof the fiber has an increasing gradient in a degree of hydrolysis of thepolymer from the interior region to the surface region.

3. The fiber according to clause 1 or 2, wherein the polymer comprisingat least one of a vinyl acetate moiety or a vinyl alcohol moietycomprises a polyvinyl alcohol homopolymer, a polyvinyl acetatehomopolymer, a polyvinyl alcohol copolymer, or combinations thereof.

4. The fiber according to any of clauses 1-3, wherein the polyvinylalcohol copolymer is a copolymer of vinyl acetate and vinyl alcohol.

5. The fiber according to any of clauses 1-3, wherein the polyvinylalcohol copolymer comprises an anionically modified copolymer.

6. The fiber according to clause 5, wherein the anionically modifiedcopolymer comprises a carboxylate, a sulfonate, or combinations thereof.

7. The fiber according to any of clauses 1-6, further comprising anadditional polymer.

8. The fiber according to clause 7, wherein the additional polymer isselected from the group consisting of: polyvinyl alcohol, polyvinylacetate, polyacrylate, water-soluble acrylate copolymer, polyvinylpyrrolidone, polyethylenimine, pullulan, guar gum, gum Acacia, xanthangum, carrageenan, starch, modified starch, polyalkylene oxide,polyacrylamide, polyacrylic acid, cellulose, cellulose ether, celluloseester, cellulose amide, polycarboxylic acid, polyaminoacid, polyamide,gelatin, dextrin, copolymers of the foregoing, and combinations of anyof the foregoing additional polymers or copolymers.

9. The fiber according to any of clauses 1-8, wherein the first degreeof hydrolysis is in a range from about 79% to about 96% and the seconddegree of hydrolysis is in a range of from about 88% to 100%.

10. The fiber according to any of clauses 1-9, wherein the first degreeof hydrolysis is in a range from about 79% to about 92% and the seconddegree of hydrolysis is in a range of from about 88% to about 96%.

11. The fiber according to any of clauses 1-10, wherein the fiber has adissolution time of less than 200 seconds in water at about 23° C.

12 The fiber according to any of clauses 1-11, wherein the fiber has ashrinkage along a longitudinal axis of the fiber in a range of fromabout 20% to about 70% while contacting water at a temperature in arange of from about 10° C. to about 23° C.

13. The fiber according to any of clauses 1-12, wherein the polymer inthe interior region has a glass transition temperature (T_(g)) in arange of from about 72° C. to about 72.9° C., and the polymer in thesurface region has a T_(g) in a range of from about 73° C. to about 85°C.

14. A fiber having a longitudinal axis and a transverse cross-sectionperpendicular to the longitudinal axis of the fiber, the fiber furtherhaving a core and sheath structure along at least a portion of thelongitudinal axis, the fiber comprising: a core region of the core andsheath structure comprising a polymer comprising at least one of a vinylacetate moiety or a vinyl alcohol moiety having a first degree ofhydrolysis less than 100%; and a sheath region of the core and sheathstructure disposed radially outward from the core region in thetransverse cross-section, the sheath region comprising the polymercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety having a second degree of hydrolysis greater than the firstdegree of hydrolysis.

15. The fiber according to clause 14, wherein the polymer comprising atleast one of a vinyl acetate moiety or a vinyl alcohol moiety comprisesa polyvinyl alcohol homopolymer, a polyvinyl acetate homopolymer, avinyl acetate and vinyl alcohol copolymer, a modified polyvinyl alcoholcopolymer, or combinations thereof.

16. The fiber according to clause 14 or 15, wherein a difference betweenthe first degree of hydrolysis and the second degree of hydrolysis is atleast 1%.

17. The fiber according to any of clauses 14-16, wherein a differencebetween the first degree of hydrolysis and the second degree ofhydrolysis is in a range of about 1% to about 29%.

18. The fiber according to any of clauses 14-17, wherein the polymer inthe core region has a first degree of polymerization and the polymer inthe sheath region has a second degree of polymerization equal to thefirst degree of polymerization.

19. The fiber according to any of clauses 14-18, further comprising anintermediate region disposed between the core region and the sheathregion in the transverse cross-section, the intermediate regioncomprising the polymer having a third degree of polymerization equal tothe first degree of polymerization and the second degree ofpolymerization.

20. The fiber according to any of clauses 14-19, further comprising anintermediate region disposed between the core region and the sheathregion in the transverse cross-section, the intermediate regioncomprising the polymer having a third degree of hydrolysis greater thanthe first degree of hydrolysis and less than the second degree ofhydrolysis.

21. The fiber according to any of clauses 14-20, further comprising anintermediate region disposed between the core region and the sheathregion in the transverse cross-section, wherein each of the core region,the sheath region, and the intermediate region comprises a modifiedpolyvinyl alcohol copolymer having a same degree of modification.

22. The fiber according to any of clauses 14-21, further comprising aplurality of intermediate regions disposed between the core region andthe sheath region in the transverse cross-section, wherein thetransverse cross section has an increasing gradient in a degree ofhydrolysis from a first intermediate region of the plurality of regionsdisposed adjacent the core region to a second intermediate region of theplurality of regions disposed radially outward from the firstintermediate region.

23. The fiber according to any of clauses 14-22, wherein the sheathregion has a second degree of hydrolysis in a range of from about 88% toabout 96% and the fiber has a dissolution time of less than 200 secondsin water at about 23° C.

24. The fiber according to any of clauses 14-23, wherein the sheathregion has a second degree of hydrolysis in a range of from about 88% toabout 96% and the fiber has a drying shrinkage in a range of from about20% to about 70% after soaking in water at a temperature in a range offrom about 10° C. to about 23° C.

25. The fiber according to any of clauses 14-24, wherein the sheathregion has a second degree of hydrolysis in a range of from about 88% toabout 96% and the polymer in the sheath region has a glass transitiontemperature in a range of from about 73° C. to about 85° C.

26. A fiber, comprising: a first region comprising a polymer comprisingat least one of a vinyl acetate moiety or a vinyl alcohol moiety havinga first degree of hydrolysis less than 100%; and a second regioncomprising the polymer comprising at least one of a vinyl acetate moietyor a vinyl alcohol moiety having a second degree of hydrolysis greaterthan the first degree of hydrolysis, wherein the polymer comprises apolyvinyl alcohol homopolymer, a polyvinyl acetate homopolymer, a vinylacetate and vinyl alcohol copolymer, a modified polyvinyl alcoholcopolymer, or a combination thereof.

27. The fiber according to clause 26, wherein the fiber has alongitudinal axis, the first region forms a core region of the fiberalong the longitudinal axis and the second region forms a sheath regionof the fiber surrounding at least a portion of the core region.

28. The fiber according to clause 27, wherein the fiber has a transversecross-section perpendicular to the longitudinal axis, the fiber furthercomprises an intermediate region disposed between the first region andthe second region in the transverse cross-section, the intermediateregion comprising the polymer having a third degree of hydrolysisgreater than the first degree of hydrolysis and less than the seconddegree of hydrolysis.

29. The fiber according to clause 27, wherein the fiber has a transversecross-section perpendicular to the longitudinal axis, the fiber furthercomprising a plurality of intermediate regions comprising the polymerand disposed between the first region and the second region, and thetransverse cross-section has an increasing gradient in a degree ofhydrolysis from the first region to the second region.

30. The fiber according to any of clauses 26-29, wherein a differencebetween the first degree of hydrolysis and the second degree ofhydrolysis is at least 1%.

31. The fiber according to any of clauses 26-30, wherein a differencebetween the first degree of hydrolysis and the second degree ofhydrolysis is in a range of from about 1% to about 29%.

32. The fiber according to any of clauses 26-31, wherein the fiber has atransverse cross-section perpendicular to the longitudinal axis, thefiber further comprises an intermediate region comprising the polymerand disposed between the first region and the second region in thetransverse cross-section, and the polymer in each of the first region,the second region, and the third region has a same degree ofpolymerization.

33. The fiber according to any of clauses 26-32, wherein the fiber has atransverse cross-section perpendicular to the longitudinal axis, thefiber further comprises an intermediate region comprising the polymerand disposed between the first region and the second region in thetransverse cross-section, and the polymer in the first region, thesecond region, and the third region comprises a modified polyvinylalcohol polymer having a same degree of modification.

34. A nonwoven web comprising the fiber according to any of clauses26-33.

35. A multilayer nonwoven web comprising a first layer comprising thenonwoven web according to clause 34.

36. A pouch comprising the nonwoven web according to clause 35 in a formof a pouch defining an interior pouch volume.

37. A sealed article comprising the nonwoven web according to clause 34.

38. A flushable article comprising the nonwoven web according to clause34.

39. A wearable absorbent article, comprising: an absorbent core having awearer facing side and an outer facing side; and a liquid acquisitionlayer, wherein the liquid acquisition layer comprises the nonwoven webaccording to clause 34.

40. A particle having a core-shell structure, the particle comprising: acore region of the core-shell structure comprising a polymer comprisingat least one of a vinyl acetate moiety or a vinyl alcohol moiety andhaving a first degree of hydrolysis less than 100%; and a shell regiondisposed radially outward from the core region, the shell regioncomprising the polymer comprising at least one of a vinyl acetate moietyor a vinyl alcohol moiety having a second degree of hydrolysis greaterthan the first degree of hydrolysis.

41. The particle according to clause 40, wherein the particle has anincreasing gradient in a degree of hydrolysis of the polymer radiallyfrom a center of the core region to an exterior surface of the shellregion.

42. The particle according to clause 40 or 41, wherein the polymercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety comprises a polyvinyl alcohol homopolymer, a polyvinyl acetatehomopolymer, a polyvinyl alcohol copolymer, or combinations thereof.

43. The particle of according to clause 42, wherein the polyvinylalcohol copolymer is a copolymer of vinyl acetate and vinyl alcohol.

44. The particle according to clause 42, wherein the polyvinyl alcoholcopolymer is anionically modified, and further comprises a carboxylate,a sulfonate, or combinations thereof.

45. The particle according to any of clauses 40-44, wherein the particlehas one of a spherical shape or an irregular shape.

46. The particle according to any of clauses 40-45, wherein the particleis one of a microsphere or a bead.

EXAMPLES Fibers Used

As shown in Table 2, four fibers, Fiber A, Fiber B, Fiber C, and FiberD, which comprise a copolymer of vinyl acetate and vinyl alcohol havinga degree of hydrolysis of 88%, 96%, 98%, and 99.99%, respectively, wereused as the starting materials. These fibers have uniform composition,and have additional properties shown in Table 2. In the Examples andComparative Examples described herein, the fibers being used have afineness of 2.2 dtex.

TABLE 2 Fiber Viscosity (4% solution) DH (mol%) Fineness (dtex)Solubility Temp (C) Tenacity (cN/dtex) Elongation (%) A 22-23 88 1.7 205 20 2.2 B 22-23 96 1.2 40 7 15 1.7 C 22-23 98 1.2 70 7 12 1.7 D 22-2399.99 1.2 95 9 10 1.7

Example 1

The samples of Fiber A, which comprises a copolymer of vinyl acetate andvinyl alcohol having a degree of hydrolysis of 88% as the sole fiberforming material were post-process hydrolyzed as follows. In theExamples, a polymer comprising vinyl alcohol moieties is referred as “apolyvinyl alcohol polymer,” and a fiber comprising such a polymer isreferred as “a polyvinyl alcohol fiber.” 5 grams (g) of the polyvinylalcohol fibers were immersed in a 10% solution of sodium hydroxide inmethanol. The fibers did not dissolve in the methanol. The resultingmixture was heated to 60° C. for 24 hours. After 24 hours, the mixturewas cooled and the fibers separated from the methanol. The resultinghydrolyzed fibers were dried to remove any residual methanol prior tomeasuring the degree of hydrolysis using the titration method disclosedherein. The degree of hydrolysis of the hydrolyzed fibers was found tobe 99.9% using the titration method.

Thus, Example 1 shows using the method of the disclosure to prepare apost-process hydrolyzed polyvinyl alcohol fiber.

Example 2

Fibers comprising a copolymer of vinyl acetate and vinyl alcohol havinga degree of hydrolysis of 88%, 92% or 96% as the sole fiber formingmaterial or in combination with other fiber forming materials arepost-process hydrolyzed as follows. 5 g of the polyvinyl alcohol fibersare immersed in a 25% solution of sodium hydroxide in a solvent ormixture (i.e., 10 % methanol and 90 % hexane by weight) thereof, havinga dielectric constant of about 20 or greater. The fibers do not dissolvein the solvent. The resulting mixture is heated to 60° C. for 12 hours.After 12 hours, the mixture is cooled and the fibers separated from thesolvent. The resulting hydrolyzed fibers are dried to remove anyresidual solvent prior to measuring the degree of hydrolysis using thetitration method disclosed herein. The degree of hydrolysis of thehydrolyzed fibers are found to be 99.9% using the titration method.

Thus, Example 2 shows using methods of the disclosure to preparepost-process hydrolyzed polyvinyl alcohol fibers.

Example 3

Fibers comprising a copolymer of vinyl acetate and having a degree ofhydrolysis of 88%, 92% or 96% as the sole fiber forming material or incombination with other fiber forming materials are post-processhydrolyzed as follows. 5 g of the polyvinyl alcohol fibers are immersedin a 10% solution of sodium hydroxide in methanol. The fibers do notdissolve in the solvent. The resulting mixture is heated to 60° C. for 1to 6 hours. After 1 to 6 hours, the mixture is cooled and the fibersseparated from the solvent. The resulting hydrolyzed fibers are dried toremove any residual solvent prior to measuring the degree of hydrolysisusing the solution titration method and the ATR-FTIR method as disclosedherein. The hydrolyzed fibers are found to have a transversecross-section having an increasing gradient in the degree of hydrolysisof the polymer an inner region to a surface region.

Thus, Example 3 shows using methods of the disclosure to preparepost-process hydrolyzed polyvinyl alcohol fibers of the disclosurehaving a transverse cross-section characterized by a gradient structure.

Example 4

Fibers comprising a copolymer of vinyl acetate and vinyl alcohol havinga degree of hydrolysis of 88%, 92% or 96% as the sole fiber formingmaterial or in combination with other fiber forming materials arepost-process hydrolyzed as follows. 5 g of the polyvinyl alcohol fibersare immersed in a 10% solution of sodium hydroxide in a 60/40 (w/w)mixture of DMSO/water. The fibers do not dissolve in the solvent. Theresulting mixture is heated to 60° C. for up to one hour. The mixture isthen cooled and the fibers separated from the solvent. The resultinghydrolyzed fibers are dried to remove any residual solvent prior tomeasuring the degree of hydrolysis using the solution titration methodand the ATR-FTIR method as disclosed herein. The hydrolyzed fibers arefound to have a transverse cross-section having a core-sheath structure,wherein only the polymer of the surface of the fiber a greater degree ofhydrolysis than the polymer of the core.

Thus, Example 4 shows using methods of the disclosure to preparepost-process hydrolyzed polyvinyl alcohol fibers of the disclosurehaving a transverse cross-section characterized by a core-sheathstructure.

Example 5

Fibers comprising polyvinyl alcohol having a degree of hydrolysis of88%, 92% or 96% as the sole fiber forming material or in combinationwith other fiber forming materials are post-process hydrolyzed asfollows. 5 g of the polyvinyl alcohol fibers are immersed in a 10%solution of sodium hydroxide in methanol. The fibers do not dissolve inthe solvent. The resulting mixture is heated to 60° C. for 1-6 hours.After 1-6 hours, the mixture is cooled and the fibers separated from thesolvent. The resulting hydrolyzed fibers are dried to remove anyresidual solvent prior to measuring the degree of hydrolysis using thesolution titration method and the ATR-FTIR method as disclosed herein.The hydrolyzed fibers are found to have a transverse cross-sectionhaving an increasing gradient in the degree of hydrolysis from aninterior region to a surface region.

Thus, Example 5 shows using methods of the disclosure to preparepost-process hydrolyzed polyvinyl alcohol fibers of the disclosurehaving a transverse cross-section characterized by an increasing degreeof hydrolysis gradient from an interior region to a surface region.

Examples 6- 46

Examples 6-46 further illustrate controlling the solubility profile ofcold-water soluble fibers by creating a “core and sheath” structure ofvarying solubility via secondary saponification reaction. Fiber Acomprising a copolymer of vinyl acetate and vinyl alcohol, which has adegree of polymerization of 1,700 and a degree of hydrolysis of 88%, wasused as a starting material. The fibers or nonwoven webs including FiberA were treated in a batch process, respectively, at a temperature in anincreasing range (20, 30, 40, 50, or 60° C.), for a period of time in anincreasing range (1, 2, 5, or 10 minutes), while maintaining the baseconcentration (0.05 M). Depending on how many fibers were to bemodified, the amount of base needed to fully saponify the sample wascalculated to determine how much base to add to the reaction. Referringto the reaction in Scheme (1), for example, the calculated amount ofNaOH needed to fully hydrolyze 3 g of the fibers (Fiber A) is 0.299 g.

The samples were made using the following procedures: Base (NaOH or KOH)pellets were crush with a mortar and pestle, then placed in a vacuumoven at 60° C. for 5 hours. Such a base was further dried in adesiccator for 12 hours prior to use, and then returned to thedesiccator after each use. Dried NaOH or KOH of a calculated amount andthe solvent of a corresponding amount of solvent were added into anErlenmeyer flask of a suitable size, so that a resulting molarity of thereaction solution was 0.05 M. A stir bar was placed into the reactionflask to ensure that the base is thoroughly dissolved in the solvent.Heat might be used to expedite the dissolution if needed. A timer andlong forceps were used. A Buchner funnel washing station with a vacuumflask and a pump was set up. The fibers of a pre-determined amount wereplaced in the reaction flask, while the timer was started. The fiberswere pulled out the reaction solution at the designated time intervals(e.g., 1, 2, 5, 10 minutes, respectively) and rinsed with methanol inthe Buchner funnel under vacuum filtration conditions. The resultingmodified fibers were thoroughly dried. The modified fibers were placedin a labeled large weigh boat and allowed to dry in a chemical hoodovernight. After the modified fibers were dried, the modified fibersample was analyzed using ATR-FTIR. This procedure was the same for awet batch process for treating Fiber A nonwoven web, except that the 2inch x 1 inch nonwoven webs (3 for each time interval) were suspended inthe solution via an alligator clamp.

The degree of hydrolysis of each resulting sample was determined by thetitration technique, which quantifies the amount of hydroxyl groupspresent on a polymer chain, and/or ART-FTIR, which quantifies the lossof acetate groups (1715 cm⁻¹ peak) in a sample. Differential ScanningCalorimetry (DSC) was used to test glass transition temperature (T_(g))values and transitions of the modified samples.

Unless expressly described otherwise, the degree of hydrolysis for afiber or a nonwoven web obtained using ATR-FTIR is with respect to thesample surface or the sheath region. The degree of hydrolysis in theinterior or core region of such a sample may be the same as that of anuntreated sample.

Example 6

Fibers (Fiber A) were treated with 0.05 M NaOH in methanol at 50° C. for10 minutes. The surfaces of the resulting modified fibers were analyzedunder ATR-FTIR. At least three fibers or three areas of the same fiberwere tested. The ATR-FTIR curves overlapped with each other without anysignificant difference. These results show identical degrees ofhydrolysis and uniform modification of the fibers under the sameconditions.

Examples 7-10

Four samples of Fiber A were treated with 0.05 M of a base (NaOH or KOH)in a solvent (methanol or 10% methanol/ 90% hexane) at 40° C. for 1minute, respectively. For these four samples, Examples 7-10, thecombinations of the base and the solvent are: KOH and methanol (MeOH),NaOH and MeOH, KOH and MeOH/hexane, and NaOH and MeOH/hexane,respectively. Comparative Example 1 is Fiber A.

Referring to FIG. 9 showing the ATR-FTIR curves of Examples 7-10 andComparative Example 1, it was found that the solvent having 10% methanoland 90% hexane catalyzes the secondary saponification of the fiberscomprising a copolymer of vinyl acetate and vinyl alcohol.

The samples of Fiber A were also treated with 0.05 M NaOH in methanol atdifferent temperatures for different time intervals, for example, at 50°C. for 1 minute, 2 minutes, 5 minutes, and 10 minutes, respectively.Based on a model derived from the rate of change in the degree ofhydrolysis, it was found that the secondary saponification is atemperature driven second order reaction.

Examples 11-22

Table 3 shows the reaction conditions and the results of Examples 11-22,which are treated fibers. The fibers were treated with NaOH. The resultsinclude degree of hydrolysis, fiber shrinkage, and glass transitiontemperature (Tg), compared to those of Comparative Examples 1 and 2,which are fibers A and B comprising a copolymer of vinyl acetate andvinyl alcohol having degree of hydrolysis of 88% and 96%, respectively,and have uniform composition and structure throughout the fibers.Examples 11-22 were treated fibers from the samples of Fiber A. Thedegree of hydrolysis values of Examples 11-22 were obtained usingATR-FTIR on the surface or sheath regions of the fibers. The degree ofhydrolysis in the interior or core region of such a sample may be thesame as that of the untreated fiber.

TABLE 3 Example No. (Fiber) Conditions: 0.05 M NaOH Average %DH (mol%)Shrinkage (%) Tg (°C) Temp (°C) Time (min) 10° C. 23° C. No. 11 40 190.90 No. 12 2 91.30 No. 13 5 92.70 No. 14 10 94.70 22.41 44.91 No. 1550 1 92.10 73.67 No. 16 2 93.90 75.67 No. 17 5 95.40 45.37 43.98 78.67No. 18 10 96.80 57.75 65.22 79.74 No. 19 60 1 93.60 No. 20 2 95.30 No.21 5 97.00 54.75 60.86 No. 22 10 97.60 53.26 53.48 Comparative ExampleNo. 1 (Fiber A) non-modified 89.20 30.54 72.32 Comparative Example No. 2(Fiber B) 96.00 no shrink 51.77 81.44

FIG. 10 shows the fiber shrinkage of different fibers having differentdegrees of hydrolysis while contacting water at a temperature of 10° C.to 23° C. Modified fibers such as Examples 11-22 outperform ComparativeExamples such as Fibers A and B in an ability to swell with water andnot solubilize immediately. The modified fiber having 96.8% of degree ofhydrolysis (Example 18) shows the highest affinity for shrinking due toits higher degree of hydrolysis in its sheath, which stays intact, whileits core having lower degree of hydrolysis swells with water. Theresulting fibers maintain their performance at different watertemperatures, for example, in the range of from 10° C. to 23° C.

As shown in Table 3, the glass transition (Tg) temperature of thetreated fibers increases with an increase in the degree of hydrolysis.In the DSC curves, a modified fiber showed a broad range of glasstransition, which suggests multiple species exist in such a fiber samplesuch as species having lower and higher degree of hydrolysis. Such aglass transition enhances manufacturing and bonding capabilities withoutsacrificing solubility.

Gel permeation chromatography (GPC) was used to test molecular weightand polydispersity of the polymer in the fiber samples before and aftertreatment. Table 4 shows the results of molecular weight andpolydispersity of the polymer in Examples 15-18 and Comparative Examples1-2. The refraction index increment (dn/dc) was 0.146 mL/g. Statisticalanalysis shows that there is no significant difference in the molecularweight and degree of polymerization of the polymer in the fiber samplesbefore and after treatment under different conditions. Only thesaponification or hydrolysis reaction occurs and non-desiredtransformations, such as esterification, degradation, and/orcrosslinking, are suppressed and controlled by using the reactionconditions described herein.

TABLE 4 Sample Description/Treatment Conditions Test Run Mn (kDa) Mp(kDa) Mw (kDa) Polydispersity (Mw/Mn) Comparative Example 2 Fiber B 150.83 67.77 117.56 2.313 2 53.20 70.11 118.43 2.226 Comparative Example1 Fiber A 1 69.56 104.78 108.25 1.556 2 71.23 107.47 113.30 1.591Example 15 Fiber A/50° C. 1 min 1 58.21 104.00 116.32 1.998 2 65.18104.77 118.60 1.82 Example 16 Fiber A /50° C. 2 min 1 60.25 102.22130.51 2.166 2 61.15 101.56 131.39 2.149 Example 17 Fiber A /50° C. 5min 1 60.19 86.58 149.12 2.477 2 58.60 84.11 149.73 2.555 Example 18Fiber A /50° C. 10 min 1 47.29 60.10 83.01 1.756 2 47.50 60.18 87.201.836

Examples 23-34

Table 5 shows the reaction conditions and the results of Examples 23-34,which are treated nonwoven webs. The nonwoven webs were treated withKOH. In the present disclosure, it was found that treatment of a samplesuch as fibers, a nonwoven web, or a block with KOH or NaOH does notmake significant difference. The results include degree of hydrolysis,softness, and solubility testing results such as rupture time anddisintegration time at 23° C., 40° C. and 60° C., compared to those ofComparative Examples 3-8. Comparative Examples 3, 5, 6, and 7 arenonwoven webs having fibers (Fiber A, Fiber B, Fiber C, and Fiber D,respectively) comprising a copolymer of vinyl acetate and vinyl alcoholhaving a uniform degree of hydrolysis of 88%, 96%, 98%, 99.99%,respectively. Comparative Example 4 is a nonwoven web having Fiber Aexposure to heat methanol (50° C. for 10 minutes). Examples 23-34 weretreated nonwoven webs comprising fibers (Fiber A). The degree ofhydrolysis values of Examples 23-34 were obtained using ATR-FTIR on thesurface or sheath regions of fibers. The degree of hydrolysis in theinterior or core region of such a sample may be the same as that of theuntreated fibers.

TABLE 5 Examples/Nonwoven Batch Reaction Conditions: 0.05 M KOH %DHSolubilities 23C Solubilities 40C Solubilities 60C N=6 people Temp Time(min) Average Rupture Time (s) Disintegration Time (s) Rupture Time (s)Disintegration Time (s) Rupture Time (s) Disintegration Time (s)Softness No. 23 40 1 92.30 5.33 16.00 1.33 2.33 1.00 1.67 No. 24 2 94.305.67 22.33 1.67 2.67 1.00 2.33 No. 25 5 95.40 5.00 22.33 1.67 2.67 1.002.67 No. 26 10 96.70 5.67 56.67 2.00 14.33 1.00 2.67 4.08 No. 27 50 193.50 4.00 15.67 1.00 2.00 1.00 2.00 No. 28 2 94.50 4.67 18.00 1.67 3.001.00 2.67 No. 29 5 96.80 6.00 60.00 2.00 7.00 1.00 2.33 No. 30 10 98.1010.00 95.00 2.67 36.33 1.00 2.67 3.75 No. 31 60 1 94.50 4.00 23.67 1.002.00 1.00 2.00 No. 32 2 96.00 5.00 76.33 1.67 4.00 1.00 2.00 No. 33 597.40 6.00 180.00 2.67 26.33 1.00 2.33 No. 34 10 98.30 11.67 180.00 4.0024.00 2.67 14.33 3.58 Comparative Example (CEx) No. 3 (Fiber A)non-modified 89.20 21.00 58.67 2.92 CEx. 4 (Fiber A, exposed to reactionconditions) 3.12 CEx. 5 (Fiber B) 96.00 103.00 176.00 7.00 28.67 CEx. 6(Fiber C) 98.00 Insoluble Insoluble CEx. 7 (Fiber D) 99.00 CEx. 8(75%Fiber B, 25% 20dpf PET) 123.33 8.67 1.98

FIG. 11 illustrates rupture time (seconds) and disintegration time(seconds) of a nonwoven web having an exemplary fiber (Fiber A) beforeand after exposed to heated methanol (e.g., at 50° C. for 10 minutes).FIGS. 12-13 show rupture time and disintegration time of nonwoven websincluding fibers having different degrees of hydrolysis. Compared tountreated nonwoven webs, the treated or modified nonwoven webs withsimilar or higher measured degree of hydrolysis show improvedsolubility. The comparative examples having higher degree of hydrolysismay show gelling and may not be dissolved in water. However, themodified fibers and nonwoven structures having high degree of hydrolysisare dissolvable in water. The modified fibers and nonwoven structuresbreak apart prior to gelation, as opposed to Comparative Example 5(Fiber B nonwoven webs).

In Table 5, the softness data is rated from 1 (rough) to 5 (soft). Thethree samples tested show much higher softness than the ComparativeExamples without treatment.

Examples 35-46

Table 6 shows the reaction conditions and the results of Examples 35-46,which are treated block samples. The block samples were made of acopolymer of vinyl acetate and vinyl alcohol having a degree ofhydrolysis being 88%. These samples were treated with KOH. Each blocksample had a size of 1.5 centimeters (cm) x 1.5 cm x 0.5 cm. Aftertreated and dried, a sample having a thickness in a range of from 0.1 mmto 0.5 mm is cut from the block sample and then tested using ATR-FTIR.The results include degree of hydrolysis values in the interior(“inner”) region and the surface (“outer”) region. FIG. 14 shows therespective ATR-FTIR curves. The secondary saponification is limited tothe surface of a tow fiber, therefore creating a higher degree ofhydrolysis in the outer region and a lower degree of hydrolysis in theinner region of the sample.

TABLE 6 Example No. (Block) Batch Reaction Conditions: 0.05 M KOH/NaOH%DH Outer Region %DH Inner Region Temp (°C) Time (min) Average AverageNo. 35 40 1 92 89.9 No. 36 2 93 89.5 No. 37 5 96.5 89.1 No. 38 10 98.489.5 No. 39 50 1 93.4 89.6 No. 40 2 96 89.3 No. 41 5 98 89.2 No. 42 1099.1 89.4 No. 43 60 1 96 89.4 No. 44 2 98 89.4 No. 45 5 98.8 89.3 No. 4610 99.3 89.8

The foregoing description is given for clearness of understanding only,and no unnecessary limitations should be understood therefrom, asmodifications within the scope of the disclosure may be apparent tothose having ordinary skill in the art.

All patents, publications and references cited herein are hereby fullyincorporated by reference. In case of conflict between the presentdisclosure and incorporated patents, publications and references, thepresent disclosure should control.

1. A fiber having a surface region and an interior region, the fibercomprising: a polymer comprising at least one of a vinyl acetate moietyor a vinyl alcohol moiety, the fiber having a transverse cross-sectionincluding the interior region comprising the polymer having a firstdegree of hydrolysis and the surface region comprising the polymerhaving a second degree of hydrolysis greater than the first degree ofhydrolysis.
 2. The fiber according to claim 1, wherein the transversecross-section of the fiber has an increasing gradient in a degree ofhydrolysis of the polymer from the interior region to the surfaceregion.
 3. The fiber according to claim 1, wherein the polymercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety comprises a polyvinyl alcohol homopolymer, a polyvinyl acetatehomopolymer, a polyvinyl alcohol copolymer, or combinations thereof. 4.The fiber according to claim 3, wherein the polyvinyl alcohol copolymeris a copolymer of vinyl acetate and vinyl alcohol.
 5. The fiberaccording to claim 3, wherein the polyvinyl alcohol copolymer comprisesan anionically modified copolymer.
 6. The fiber according to claim 5,wherein the anionically modified copolymer comprises a carboxylate, asulfonate, or combinations thereof.
 7. The fiber according to claim 1,further comprising an additional polymer.
 8. The fiber according toclaim 7, wherein the additional polymer is selected from the groupconsisting of: polyvinyl alcohol, polyvinyl acetate, polyacrylate,water-soluble acrylate copolymer, polyvinyl pyrrolidone,polyethylenimine, pullulan, guar gum, gum Acacia, xanthan gum,carrageenan, starch, modified starch, polyalkylene oxide,polyacrylamide, polyacrylic acid, cellulose, cellulose ether, celluloseester, cellulose amide, polycarboxylic acid, polyaminoacid, polyamide,gelatin, dextrin, copolymers of the foregoing, and combinations of anyof the foregoing additional polymers or copolymers.
 9. The fiberaccording to claim 1, wherein the first degree of hydrolysis is in arange from about 79% to about 96% and the second degree of hydrolysis isin a range of from about 88% to 100%.
 10. The fiber according to claim1, wherein the first degree of hydrolysis is in a range from about 79%to about 92% and the second degree of hydrolysis is in a range of fromabout 88% to about 96%.
 11. The fiber according to claim 1, wherein thefiber has a dissolution time of less than 200 seconds in water at about23° C.
 12. The fiber according to claim 1, wherein the fiber has ashrinkage along a longitudinal axis of the fiber in a range of fromabout 20% to about 70% while contacting water at a temperature in arange of from about 10° C. to about 23° C.
 13. The fiber according toclaim 1, wherein the polymer in the interior region has a glasstransition temperature (T_(g)) in a range of from about 72° C. to about72.9° C., and the polymer in the surface region has a T_(g) in a rangeof from about 73° C. to about 85° C.
 14. A fiber having a longitudinalaxis and a transverse cross-section perpendicular to the longitudinalaxis of the fiber, the fiber further having a core and sheath structurealong at least a portion of the longitudinal axis, the fiber comprising:a core region of the core and sheath structure comprising a polymercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety having a first degree of hydrolysis less than 100%; and a sheathregion of the core and sheath structure disposed radially outward fromthe core region in the transverse cross-section, the sheath regioncomprising the polymer comprising at least one of a vinyl acetate moietyor a vinyl alcohol moiety having a second degree of hydrolysis greaterthan the first degree of hydrolysis.
 15. The fiber according to claim14, wherein the polymer comprising at least one of a vinyl acetatemoiety or a vinyl alcohol moiety comprises a polyvinyl alcoholhomopolymer, a polyvinyl acetate homopolymer, a vinyl acetate and vinylalcohol copolymer, a modified polyvinyl alcohol copolymer, orcombinations thereof.
 16. The fiber according to claim 14, wherein adifference between the first degree of hydrolysis and the second degreeof hydrolysis is at least 1%.
 17. The fiber according to claim 14,wherein a difference between the first degree of hydrolysis and thesecond degree of hydrolysis is in a range of about 1% to about 29%. 18.The fiber according to claim 14, wherein the polymer in the core regionhas a first degree of polymerization and the polymer in the sheathregion has a second degree of polymerization equal to the first degreeof polymerization.
 19. The fiber according to claim 14, furthercomprising an intermediate region disposed between the core region andthe sheath region in the transverse cross-section, the intermediateregion comprising the polymer having a third degree of polymerizationequal to the first degree of polymerization and the second degree ofpolymerization.
 20. The fiber according to claim 14, further comprisingan intermediate region disposed between the core region and the sheathregion in the transverse cross-section, the intermediate regioncomprising the polymer having a third degree of hydrolysis greater thanthe first degree of hydrolysis and less than the second degree ofhydrolysis.
 21. The fiber according to claim 14, further comprising anintermediate region disposed between the core region and the sheathregion in the transverse cross-section, wherein each of the core region,the sheath region, and the intermediate region comprises a modifiedpolyvinyl alcohol copolymer having a same degree of modification. 22.The fiber according to claim 14, further comprising a plurality ofintermediate regions disposed between the core region and the sheathregion in the transverse cross-section, wherein the transverse crosssection has an increasing gradient in a degree of hydrolysis from afirst intermediate region of the plurality of regions disposed adjacentthe core region to a second intermediate region of the plurality ofregions disposed radially outward from the first intermediate region.23. The fiber according to claim 14, wherein the sheath region has asecond degree of hydrolysis in a range of from about 88% to about 96%and the fiber has a dissolution time of less than 200 seconds in waterat about 23° C.
 24. The fiber according to claim 14, wherein the sheathregion has a second degree of hydrolysis in a range of from about 88% toabout 96% and the fiber has a drying shrinkage in a range of from about20% to about 70% after soaking in water at a temperature in a range offrom about 10° C. to about 23° C.
 25. The fiber according to claim 14,wherein the sheath region has a second degree of hydrolysis in a rangeof from about 88% to about 96% and the polymer in the sheath region hasa glass transition temperature in a range of from about 73° C. to about85° C.
 26. A fiber, comprising: a first region comprising a polymercomprising at least one of a vinyl acetate moiety or a vinyl alcoholmoiety having a first degree of hydrolysis less than 100%; and a secondregion comprising the polymer comprising at least one of a vinyl acetatemoiety or a vinyl alcohol moiety having a second degree of hydrolysisgreater than the first degree of hydrolysis, wherein the polymercomprises a polyvinyl alcohol homopolymer, a polyvinyl acetatehomopolymer, a vinyl acetate and vinyl alcohol copolymer, a modifiedpolyvinyl alcohol copolymer, or a combination thereof.
 27. The fiberaccording to claim 26, wherein the fiber has a longitudinal axis, thefirst region forms a core region of the fiber along the longitudinalaxis and the second region forms a sheath region of the fibersurrounding at least a portion of the core region.
 28. The fiberaccording to claim 27, wherein the fiber has a transverse cross-sectionperpendicular to the longitudinal axis, the fiber further comprises anintermediate region disposed between the first region and the secondregion in the transverse cross-section, the intermediate regioncomprising the polymer having a third degree of hydrolysis greater thanthe first degree of hydrolysis and less than the second degree ofhydrolysis.
 29. The fiber according to claim 27, wherein the fiber has atransverse cross-section perpendicular to the longitudinal axis, thefiber further comprising a plurality of intermediate regions comprisingthe polymer and disposed between the first region and the second region,and the transverse cross-section has an increasing gradient in a degreeof hydrolysis from the first region to the second region.
 30. The fiberaccording to claim 26, wherein a difference between the first degree ofhydrolysis and the second degree of hydrolysis is at least 1%.
 31. Thefiber according to claim 26, wherein a difference between the firstdegree of hydrolysis and the second degree of hydrolysis is in a rangeof from about 1% to about 29%.
 32. The fiber according to claim 26,wherein the fiber has a transverse cross-section perpendicular to thelongitudinal axis, the fiber further comprises an intermediate regioncomprising the polymer and disposed between the first region and thesecond region in the transverse cross-section, and the polymer in eachof the first region, the second region, and the third region has a samedegree of polymerization.
 33. The fiber according to claim 26, whereinthe fiber has a transverse cross-section perpendicular to thelongitudinal axis, the fiber further comprises an intermediate regioncomprising the polymer and disposed between the first region and thesecond region in the transverse cross-section, and the polymer in thefirst region, the second region, and the third region comprises amodified polyvinyl alcohol polymer having a same degree of modification.34. A nonwoven web comprising the fiber according to claim
 26. 35. Amultilayer nonwoven web comprising a first layer comprising the nonwovenweb according to claim
 34. 36. A pouch comprising the nonwoven webaccording to claim 35 in a form of a pouch defining an interior pouchvolume.
 37. A sealed article comprising the nonwoven web according toclaim
 34. 38. A flushable article comprising the nonwoven web accordingto claim
 34. 39. A wearable absorbent article, comprising: an absorbentcore having a wearer facing side and an outer facing side; and a liquidacquisition layer, wherein the liquid acquisition layer comprises thenonwoven web according to claim
 34. 40. A particle having a core-shellstructure, the particle comprising: a core region of the core-shellstructure comprising a polymer comprising at least one of a vinylacetate moiety or a vinyl alcohol moiety and having a first degree ofhydrolysis less than 100%; and a shell region disposed radially outwardfrom the core region, the shell region comprising the polymer comprisingat least one of a vinyl acetate moiety or a vinyl alcohol moiety havinga second degree of hydrolysis greater than the first degree ofhydrolysis.
 41. The particle according to claim 40, wherein the particlehas an increasing gradient in a degree of hydrolysis of the polymerradially from a center of the core region to an exterior surface of theshell region.
 42. The particle according to claim 40, wherein thepolymer comprising at least one of a vinyl acetate moiety or a vinylalcohol moiety comprises a polyvinyl alcohol homopolymer, a polyvinylacetate homopolymer, a polyvinyl alcohol copolymer, or combinationsthereof.
 43. The particle according to claim 42, wherein the polyvinylalcohol copolymer is a copolymer of vinyl acetate and vinyl alcohol. 44.The particle according to claim 42, wherein the polyvinyl alcoholcopolymer is anionically modified, and further comprises a carboxylate,a sulfonate, or combinations thereof.
 45. The particle according toclaim 40, wherein the particle has one of a spherical shape or anirregular shape.
 46. The particle according to claim 40, wherein theparticle is one of a microsphere or a bead.